Can confirm that this does work perfectly for Lutris, for upgrades at least. I've got my home directory on an NVMe drive and my games installed on a slower disk; as long as you don't move or rename any of the partitions, it just keeps rocking along.

My laptop and desktop have a different list of games installed, but because Lutris uses SQLite as its backing store, it's not terribly easy to keep 'some parts' synchronised and others not. I've spent a bit of time getting all of the icons, banners, release dates, etc all correct and looking pretty, and it's a shame that it's tough to reuse. (Lutris does this automatically for Wine installs if you get the name 'just right' to start with, but not for all your other emulated stuff - all the DOS games and things.)