Avast Firewall question

I have the firewall on , medium risk zone now.

But i want maximum protection , if i raise it to high risk zone , will my internet still work good ?

There are 3 computers connected to a router in the house i live in , will the connection still be good and fluid if i do it the the high risk zone setting ?

And what will change if i change it to high setting ?

Yes, that level protection is about the connections that could be done over your network (some shared services could stop working but they’re generally related to media sharing). Internet will work fine.