Penpot works perfectly on Linux, and you can even host it yourself in your own computer if you want. It's web-based and works in both Firefox and Chromium browsers. (I think WebKit ones too, but it's been a little while since I've tried it with Epiphany.)

I use Penpot myself all the time on Linux, but I'm usually using the hosted version so I can collaborate with others without having to maintain a server. I have also run locally in a container using Podman, even with Podman's rootless support.

But to start using it, all anyone needs to do is point their browser of choice to https://design.penpot.app/ and sign in. There is no setup process or installation needed; self-hosting is completely optional.