Hello, complete noob looking for help.

I live in a large concrete house(3 floors). I have a switch TL-SF1016D which then splita into different parts of my house.

In different rooms I either have lan cable or wi-fi routers, everything is comming from above mentioned TL-SF1016D.

I have a fiber network with the speed of 100 Mbps. I want to buy a 6e roiter for my top floor which I’ll use to stream games from my PC and PS5 into my steam deck(new steam deck supporta 6e). Now my queations are:

1. if I buy TP Link AXE75 5400 tri-band wifi 6e router, will I be bottlenecked because of my switch?
2. when doing local file transfers and/or lockal streaming does speed of network provider matter? Or is it only dependant on speed of my switch?
3. are there any benefits of high speed routers/switches if network provider only provides up to 100 Mbps?

Thank you in advance !