Waiting vs Acting?

You have defined your problem in a way that causes you stress and suffering. You’re feeling the stress, but you’re not comprehending it. You don’t see exactly where the stress originates. You don’t know how to cause it to cease.

I’m redefining the problem for you by splitting into two problems. The first problem: how to mitigate or eliminate stress, and live a happy life instead of a stressful one. The second: how to meet basic physical and emotional needs, in a harmless way.

The Buddha had much to say about the first problem—suffering. In fact, it’s all he taught: stress, and the ending of stress.

In tackling the first problem, he also dealt with the second problem in what he called Right Livelihood. Right Livelihood is included in his teachings on how to distinguish skillful from unskillful action, and learning how to skillfully choose those actions that lead to long term welfare and happiness over those that lead to harm and suffering.

When we underestimate the importance of the stress we experience, it tends to get ignored, grow, and overwhelm. The teachings of the Buddha are all about dealing with stress and suffering—in very pragmatic and ingenious ways—and before we are overwhelmed and incapacitated by it.

From Awareness Itself:

Another student disappeared for several months, and on her return told Ajaan Fuang, "The reason I didn't show up is that my boss sent me to night school for a semester, so I didn't have any time to meditate at all. But now that the course is over, I don't want to do anything but meditate — no work, no study, just let the mind be still."

She thought he'd be pleased to hear how intent she still was on meditating, but he disappointed her. "So you don't want to work — that's a defilement, isn't it? Whoever said that people can't work and meditate at the same time?"

If you want to remain a lay person, a householder, then you have no choice but to ensure you have right livelihood for lay persons (Vanijja Sutta). It should not stop you from meditation (Piti Sutta).

What does Buddhism say about waiting vs acting?

I don't know, and I'm not sure it's possible to say something about so general a question.

Instead I guess it may suggest either of two courses of action:

• "Acting to end kamma" -- in context perhaps this might mean, "seeing the samsara and dukkha of chasing after money, I abandon that pursuit" and instead perhaps take up life as a monk.
• "Right livelihood" as it's prescribed for laypeople -- working to earn a living and using money well

How does Buddhism prescribe navigating through such a conundrum?

One answer might be that Buddhism recommends a "middle way" which "avoids extremes".

In this case your two extremes are

"I don't want to be acting on the fear of going broke, I also don't want to go back to my old job."

... so can you consider doing neither of those -- see also "false dichotomy".

Might there be any other work in the world for you, other than, "working for aggressive profit"?

I found a job with a company developing software for the medical devices in hospitals, and it doesn't pay as well as the "FinTech" industry, but I "felt drawn towards it" as a worthwhile activity or honest living.

The top lay disciple (Agga-upasaka) Citta Gahapati had chosen a Celibate life without using money. Even the Ghatikara Upasaka in Kassapa Buddhas time made living by exchanging goods without using money while being a Brahmacari.

For the people who are unable to live such a life there are suttas that worth reading to get advises and clues about the proper Upasaka life while earning money.

Eg: Mangala, Sigalovada, Upasaka, Alavaka ..etc.

In Zen and Vajrayana subcategories of Mahayana Buddhism, acting vs waiting is a core problem to be solved by the student as she or he transitions from studying Buddhism as a theory to mastering the Dharma in practice.

You see, the key point of Dharma is realization of suchness (tathata), and a key aspect of suchness is being authentic in one's relationships with the world. To be authentic requires finding one's so-called true self or true nature (which is usually stuck waiting), liberating it from mental and emotional obscurations, and nurturing its power to act.

As my Zen Master loved to repeat, trying to find a perfect job is "the hunting dog mind" - running around, panting, chasing the squirrels, getting itself exhausted in the hope of catching something worthwhile. Instead, he taught, the perfect job grows (right where you are, wherever you are!) from your authentic action, which itself grows from the root of having found oneself.

When you act from your authentic core, the crude dichotomy of action vs inaction no longer applies. At that point there's no waiting for the next thing to find you, nor hunting dog mind - there is authentic expression of truth unfolding moment by moment, and the truth never fails, even if you don't yet know where it is taking you.