Afaik yes, Lutris is a desktop only app. I’m not aware of any plugins. I use it both on my linux desktop, HTPC for gaming, and deck.
I would recommend setting your games up and then trying to start them a couple times from Lutris. Once you’re happy, then add the shortcut to Steam and pretend like Lutris doesn’t exist.
14 year old me would be all over this advice. In fact, it was all over him, like a thick layer of woman repellant