Severe performance issue on day one is most likely a bug, some incompatibility, or debug code accidentally left in.
I don’t know why people interpret it as if the game will never be playable and behave as if it was some master plan to make 4090 look slow.
I buy everything I can on GoG due to lack of DRM. If something is not on GoG, I buy from Epic simply because they pay a bigger share to developers than Steam. When I buy a game I want that money go to the devs, not middlemen.
GoG also integrates well with Epic, so I can have all my games there.