@izaya how are you streaming it? I'm not familiar with RimWorld: is it point and click? I've tried streaming a couple games running on Proton--one, a 3D MMORPG, and the other, a 3D adventure game--from my desktop to my laptop before with Steam's built-in streaming tools, but I ran into issues with input/peripherals and one weird camera issue that made both games I tried unplayable.
@izaya I guess you use a VPN to connect over the internet? I only ever tried remote play when I was on the same LAN...but I didn't ask too many questions about how it actually worked.