Current version of Gran Turismo 7 is 109.2gb and obviously that will increase with updates.
GTAV is 92gb, Horizon forbidden west is 99gb, it's just how big games are these days.
Gone are the days of loading a cassette for several hours or storing a single photo on a 1.4mb floppy disk.
The easiest part of that to answer is the Switch, steer clear. I had one a while back and it's just a gimmick that will very quickly gather dust. It's very much aimed at kids. Graphically still a generation behind.
The other two are so similar it's all about preference and what exclusives...