What is it like to perceive without 5 Skandas?

Purification..., Liberation..., Nibbana...

The Buddha Himself in the Nibbana Sutta, Udana 8.1:

"Nibbana... that dimension where there is neither earth, nor water, nor fire, nor wind; neither dimension of the infinitude of space, nor dimension of the infinitude of consciousness, nor dimension of nothingness, nor dimension of neither perception nor non-perception; neither this world, nor the next world, nor sun, nor moon. And there, I say, there is neither coming, nor going, nor stasis , neither passing away nor arising: without stance, without foundation, without support. This, just this, is the end of dukkha."

If body is not needed, then is Nibbana attained only at death?

According to the Pali text references are made to Nibbana as sopadisesa and anupadisesa. These, in fact, are not two kinds of Nibbana, but the one single Nibbana, receiving its name according to the way it is experienced before and after death. - Buddhism in a Nutshell - Nibbana

What is it like to be without skandas?

You cannot exist without skandas. Nibana is like the flame blowout.

I could not perceive the state as we are constantly bombarded with internal and external stimulations which makes me assume that this state can never be achieved and only an incremental change towards nibbana can happen.

Yes. It is a gradual process where you pass multiple stages before the glimpse of Nirvana and also after until final Arahatship.

"What's it like to be without the five skandhas?"

If you read the Heart Sutra, "Avalokiteshvara saw the five skandhas to be empty [of essence, empty of having a self, selfless, empty of an 'independent individual'].

This means that it is not the five skandhas that we are trying to abandon, we are simply trying to see them clearly and without beliefs.

The Five Aggregates or Heaps or you might even say Piles or Sediment are:

• Form (or we can say "matter")
• Feeling (physical awareness)
• Perceptions (sounds, smells, tastes, touches, identified and pre-identified [or without labeling])
• Formations (such as birth, death, figments of continuity over moments)
• Consciousness

With enough relaxed meditation, relaxing the speech and the thinky/discursive mind, one can collect and attune their pervasive-attentiveness to an investigation of self and if all the aggregates are truly selfless, as is taught.

Metta and joy. Just offering some notes to aide, perhaps they will be helpful.

What is it like without the 5 Skandas?

Speaking from personal experience, I would say it probably a place of healing. It's not a "black and white" state (it doesn't have a clear demarkation). When a meditator focuses on the present moment, they lose all sense of self and the five aggregates that you mention. They don't feel anything when they are in that state, but only when they "return" do they feel the benefits of escaping. The first thing they notice upon returning is the effects of the absence of the constant chatter of the mind. It's like there was a jackhammer constantly running in the background and for the duration of the session it had stopped. It's almost like being asleep, but its different. Letting go is difficult though.

if 5 skandas are overcome, does one really need a body? If body is not needed, then is Nibbana attained only at death?

I'm not sure about this one. The Buddha encourage one to stay away from metaphysics.

Nibbana is the 5 skandas have overcome the idea of a "person" & "who".

The Pali scriptures define Nibbana as the end of greed, hatred & delusion and occurring to a living conscious mind. The following is merely one teaching from many:

Here a bhikkhu is an arahant, one whose taints are destroyed, the holy life fulfilled, who has done what had to be done, laid down the burden, attained the goal, destroyed the fetters of being, completely released through final knowledge. However, his five sense faculties remain unimpaired, by which he still experiences what is agreeable and disagreeable and feels pleasure and pain. It is the extinction of attachment, hate and delusion in him that is called the Nibbana-element...

Iti 44