[ksec]

>is it theoretically possible to have cooling paste be jelly like?

That is already available and used in some Laptops. Look up Honeywell thermal pad.

The problem is as always, cost.

[numpad0]

I thought thermal pads are generally thicker and less performant

[IlGrigiore]

There are thermal pads that perform equally or better than thermal pastes, due to their design. In particular, something like https://thermalmanagement.honeywell.com/us/en/products/therm... can be better than a good thermal paste like https://www.thermal-grizzly.com/en/products/16-kryonaut-en. The thermal conductivity is improved due to the use of a phase shifting material. Reliability is improved due to the fact that it will naturally return to solid without cracking during heat cycling.