It runs on Linux natively. Works well for me (installed via Steam).

Same goes for all the extensions. The Linux version is really solid.

The performance is a fraction of that on Windows though, from my experience.

Might this be a memory issue? I run it on Xubuntu and noticed it sometimes uses all my 8GB RAM so the PC starts swapping.

It loves RAM (and probably RAM speed), but not necessarily in a bad way. Jumping to 16gb (2x8gb) from 8gb (1x8gb) on the laptop I first played it on was a big jump in performance even with a GT740.

Yeah, C:S will gobble RAM like there's no tomorrow, especially if you've got a lot of mods installed.

Not my experience. Performance is pretty equal for me, always a bit laggy.

Yep, works perfectly on Archlinux through Steam for me as well

I tried installing it on Ubuntu MATE, GPD Pocket 2, with whatever the display-scaling default is for this distro. There is some stupid bug where I can't get past the privacy-policy adhesion agreement because it is rendered mostly off screen and doesn't recognize keyboard input. Classic Linux desktop paper-cut that I'm sure I could resolve with 15-240 minutes of web research.

Other than that, I assume the Linux version is fine.