Remove free to play games

You should be able remove them in steam account licenses page

As xxxka said it's here. Just searh for "remove" buttons

https://steamcommunity.com/sharedfiles/filedetails/?id=756281375

The profile limited games aren't shown in the game number on steam.
So the F2p and demos are, not only, the source of the different numbers.

right click them on your library, then manage, then remove from account

There are also games that don't have a Steam page anymore or not in sale, which Steam profile doesn't count them.