Yeah, my t300rs worked on linux but that's because there's a kernel module for it. Which it looks like they have expanded since I last took a look, so that's cool. But I ditched it for the DD ffboard a while back.
In terms of rally games not working, which ones are you having trouble with? I play all the big ones that people talk about and haven't had any issues but I don't have a moza wheel so I'm not sure what specific issues those have. Apart from EA WRC which doesn't run anyway (and when it did I never thought it was that great of a game). ACR has input issues on windows too unfortunately.
The SROL discord can be pretty helpful since it was started by a couple of very active developers in that space including the dev responsible for universal-pidff. I think the situation is quite good and always improving, but still depends a little bit on what hardware you have. There are some less popular wheels that are completely unsupported still. It also doesn't help that iracing and EA are actively hostile to the linux community.