DigiKam, RAWTheropee, and DarkTable all support RAW images. There are a couple plugins for GIMP that support RAW too
If you just looking for a small desktop why not just pickup a Meerkat from System76?
I've used raw therapee and it's quite nice, I found it had the tendency to induce green fringing in some cases. Now this could be a lens correction profile issue. I didn't notice it in Lightroom. The images on windows Lightroom looked a bit better.
I've found dark table about as counterintuitive as gimp
Still, I intend to keep trying.
Another reason I've not done system 76 or something like that is because I want to do it myself, like I used to years ago. Still, I'll check it out.
--
Edit
Priced out a meerkat for about 640. Base everything