Honestly, it’s probably not worth the hassle to try to install system apps elsewhere. Steam and Lutris, on the other hand, can put games on any mounted drive. Install them as normal, and then in Steam, set up a steam library in /Apps
. In Lutris, you should have the option to choose where each game is installed each time you install one.
The Twitter thread says that the website with the linked keys is a fake imposter site. Not sure how true that is, but if so, that’s fucked.