Is it okay to seek financial gains as a layman?

Accumulation of wealth is not directly the problem in Buddhism, rather it is the attachment to wealth that creates suffering. Wealth and fame are ephemeral so relying on these for happiness is like walking on a frozen lake. You don't have to give away all your possessions or go to the top of the mountain for enlightenment/nirvana. Start with the present moment.

The Buddha does outline some vocations that go against Buddhism such as those dealing with the buying and selling of arms and poisons.

It's always possible to give away wealth to good causes which is helpful karma. Nonetheless, your question reminds me of the Tao Te Ching which is appropriate here: it is easier to carry a half-filled cup than one that is filled to the brim.

Nope: with lots of money (or lots of anything valuable), you can influence/help people and have time to cultivate.

Thus, the Buddha would encourage making money--but not at the behest of ignoring the rest of the Eightfold Path! My teacher always said that the people with high cultivation in this day will strangely enough be the ones successful in business because they will have the right conditions to practice and share Dharma--while the others will not, minds plagued with un-managed concerns, need, greed, and suffering.

From Wikipedia entry for Right Livelihood:

"And what is right livelihood? Right livelihood, I tell you, is of two sorts: There is right livelihood with effluents, siding with merit, resulting in acquisitions; there is right livelihood that is noble, without effluents, transcendent, a factor of the path.

"And what is the right livelihood with effluents, siding with merit, resulting in acquisitions? There is the case where a disciple of the noble ones abandons wrong livelihood and maintains his life with right livelihood. This is the right livelihood with effluents, siding with merit, resulting in acquisitions.

"And what is the right livelihood that is noble, without effluents, transcendent, a factor of the path? The abstaining, desisting, abstinence, avoidance of wrong livelihood in one developing the noble path whose mind is noble, whose mind is without effluents, who is fully possessed of the noble path. (...)

The early canonical texts state right livelihood as avoiding and abstaining from wrong livelihood. This virtue is further explained in Buddhist texts, states Vetter, as "living from begging, but not accepting everything and not possessing more than is strictly necessary".[57] For lay Buddhists, states Harvey, this precept requires that the livelihood avoid causing suffering to sentient beings by cheating them, or harming or killing them in any way.[28]

TLDR:

Scripture says at the minimum so long as you're not taking advantage of people or harming them it is OK.

If you can't make an ostensible positive impact through your line of work then use the loads of cash that you are making to help others become more at peace and free.

I think of the Sigalovada Sutta as summary of practical morality for lay people:

• Consider all the various types of people around you in society (the "six directions")
• Don't harm people around you, instead protect and make peace with them
• Don't squander wealth, but spend it and save it for the various purposes for which it should be spent and saved
• Have good-hearted friends, rather than enemies disguised as friends

I also recommend a book, The Buddha's Teachings on Prosperity by Bikkhu Basnagoda Rahula. It's a selection or anthology of suttas from the Pali canon, divided into various chapters by topic (preview the table of contents here). Many or even most of the suttas in the whole canon are for monks, so I found that this book (which selects those intended for lay people) gave quite a different impression of what lay life is supposed to be.

This article, Dhamma, says that "the Buddha's six-stage gradual training" begins with Generosity.

For more about Buddhist lay morality, consider the Five (or Eight or more) Precepts (including "don't steal" or "take what's not given", and "don't lie"), and the three factors (right speech, action, and livehood) from the "Virtue" division of the Noble Eightfold Path.

The advice for "Right Speech" is more detailed than the advice for a lay-person's Right Livelihood. If you're in a "very competitive" environment there may be a risk that people around you speak in harsh or cruel ways: maybe that (right speech versus wrong speech) is something to beware of more than simply earning a livelihood.

There are various types of wrong livelihood listed, and we're told to give up or renounce "false (or wrong) livelihood" which presumably includes lying and deception.

In short, is having a goal of seeking financial success and money considered an attachment to the world?

I think so, yes, but it isn't everyone who wants to be or who can be a monk (monks have no livelihood at all as such, and live via the generosity of laypeople).

Still, Buddhism (especially later Buddhism e.g. Mahayana rather than Theravada) has doctrine that includes "skillful means". Many non-Buddhist cultures think you're clever if you're rich but not attached to wealth. I can't confirm from my own experience whether that's possible in practice, though there are examples in the literature of rich people being generous.

Also your intention matters. If you're earning money to spend on showing off, to increase your pride, to spend on "recreational" drugs, etc., maybe that's not wise. If you're earning money to help other people or to repay your debts to society then maybe that's not unwise (and even if it may be attachment, isn't the same especially unskillful kind of attachment).

The Zen story Publishing the Sutras seems to me an example of non-attachment within attachment: attachment (or dedication) to collecting money with a specific end in mind, and non-attachment in being able to renounce or change that goal if circumstances change.

It's presumably easy, though, to spend your life on the accumulation of money.

There are incidentally different schools or sects of Buddhism.

One of the newer ones is Soka Gakkai International (SGI) -- I know next to nothing about them but perhaps they're quite keen on prosperity. I am probably misrepresenting them (you should find out for yourself, if you're interested) but I provisionally categorize it as a Buddhist version of Prosperity theology.

Original Pali Buddhism makes a clear distinction between the monks & the lay followers. If you are a lay person, generally you must earn a living or wealth, i.e., 'money'.

The Buddha praised laypeople who were skilled at making money in a harmless enough manner, particularly when they were not attached to & shared their wealth (SN 42.12).

There, Gāmaṇi, the one partaking sensuality amassing wealth by righteous means and non forceful means, who with that wealth pleases himself, shares with others and does merit, not greedy, not infatuated and innocent about that wealth he partakes in it seeing the danger and wise about the escape from it. Gāmaṇi, this one partaking sensuality is praised for these four counts. What four? Amasses wealth righteously and non-forcefully this is the first praise. He pleases himself this is the second praise. He shares and does merit, this is the third praise. He is not greedy, not infatuated, innocent about that wealth and partakes it seeing the danger and wise about the escape from it. This is the fourth praise.

Rāsiyo Sutta

In short, Buddhism does not extol poverty & recognises Livelihood as a requisite of life (rather than as an attachment).

However, if money is used for engaging in unwholesome types of sensual pleasures & vain luxury, which lead to strong addictions & egoism, this is contrary to the Buddhist way of life (since addictions & egoism generate suffering).

Some more quotes below:

he/she reappears in the plane of deprivation...This is the way leading to poverty...MN 135

~~~

There are these four kinds of bliss that can be attained in the proper season, on the proper occasions, by a householder partaking of sensuality. Which four? The bliss of having, the bliss of [making use of] wealth, the bliss of debtlessness, the bliss of blamelessness. AN 4.62

~~

The wise and virtuous shine like a blazing fire. He who acquires his wealth in harmless ways like to a bee that honey gathers, riches mount up for him like ant hill's rapid growth.

With wealth acquired this way, a layman fit for household life, in portions four divides his wealth: thus will he friendship win.

One portion for his wants he uses, two portions on his business spends, the fourth for times of need he keeps.

Sigalovada Sutta

Contrary to the popular belief, Buddhist way of life does not start with the eradication of attachment.Detached nature is a quality of final realization but definitely not the main part of the process. The noble eight fold path starts with right-view(Samma Ditti). If the path is correctly followed, the final destination will be free of suffering which is caused by attachment. Worldly beings are attached to the sensual world due to a false view(ignorance). Therefore, it is important to clear the vision first rather than removing attachment. Because it would be something forceful and artificial which leads to more problems. This is clearly evident in Buddha's main lay disciples such as Anatapindika, Vishakha or King Bimbisara who were successful in worldly life as well as supra-mundane life.

All in all, aspiring financial success is not against the path as long as you are doing it in a right way(Samma Ajiva) and your main goal in life is the cessation of suffering.