For me, Opus 5 has seemed to compete with Fable on quality of output. Prior to Opus 5 though, the previous Opus models did seem to decline once Fable was release. That's just my experience though.
What's the repository link? I think it would be fascinating to have a corpus of "hacked" solutions like this. Can't tell you how many times a couch co-op game night got sabotaged by some piece of hardware failing to communicate with another.
The "linux" support is pretty narrow (because I made this for myself). It's restricted to SteamOS. But I'm sure it could be ported easily, the repository contains documentation about the important parts from reverse engineering the firmware.
I've been going a step further and trying to get AI to decompile the firmware to a different controller to add native SInput support. Hasn't been going well.