How Will L2 affect ETH Supply?

Im sure this has been answered often but:

ETH is deflationary, and soon L2's will be where everything is done. When you use Polygon, do you pay the feee in ETH or Poly? Same goes for other potential chains if they make their own coin(Arbi/Opti).

If the fee is paid in their own coin, then the burn rate will be much lower than what we think right now? Or when the fees greatly drop + no fees are paid in ETH, how will that work out.

Basically, when you use L2, will it reduce the burn of ETH or are the fees still paid in ETH regardless