Had no Problems with that in FF14, Remnant 2, Satisfactory, Supermarket Together and Subnautica Below Zero. Tested them all under Sway, not sure how much that influences these results.

From my experience using it: Mostly steam overlay and clipboard copy/paste not working. The rest seems fine.

Most of the stuff on GoG should fit the bill. You still can use it as a website to shop for a game and get a installer exe for it. Without any additional launcher.

As far as documented network go, I’ve never seen more than games listing a couple of ports for servers, never anything like ips or actual network protocol descriptions. I guess anything with user hostable dedicated servers should be fine.

Problem is that those old games have very low online population, so I’m not entirely sure how much “casual comraderie” you’ll find.

Normal business users are fine if the Company hasn’t deep-throated Microsoft. Our Company does all the business work with no windows machine in the whole company.

Being locked-in on Microsoft Office is a thing and not the fault of linux