I know nothing about C.A.D. software, but have you heard of Steam Onlinex? It's only been a thing for quite a while, and is very popular, and has a decent chunk of games. 

 Yes. I don't game, but steam works pretty well on some flavors of Linux. But... It's not the same as having an Xbox account or being able to natively run big titles.  

 I agree; some work even better on Linux because of Proton ✌️😏