LinuxMusicians

I'm currently using a Behringer X32 digital mixer with my Linux machine. It works well, but I'm not crazy about the sound and bulky form factor and I'm thinking of replacing it. In a prior life, I worked in a recording studio and got to work with high-end converters (Apogee, Metric Halo, Lynx, etc.) and I'm a little spoiled. I also have a TC Studio Konnekt 48 that sounds great but I never did get it working with Linux, and as it's Firewire I'm concerned about the longevity of it in any case.

I'm looking for a good interface with at least 8x8 i/o, better than the typical Focusrite/Behringer/Presonus stuff people tend to recommend. RME UFX is a little out of my pricerange. Something like Antelope Zen or Discrete 8 would probably be doable if purchased used, but I'm not sure if those are really class-compliant or not.

Since you mention RME, what about the UCX (depending on pricing wherever you are) or even the Babyface?
Personally, the UCX is where I expect to go when two channels just aren't enough any more, as it has a class-compliant mode.

The TC Konnekt 48 is supported by ALSA since kernel 4.18

Yes, I just did a fresh install of Ubuntu 18.04 with a low-latency kernel and the StudioKonnekt is detected and system sounds will play through it. I'm still kind of struggling with trying to get it to work with jack and apps, but that's a topic for another thread.

I should mention that I decided to hang on to my X32 for now. I don’t love how bulky it is, and the sound quality is mediocre (for studio use- it’s great for live work.) But it does work flawlessly with Linux. In the meantime, I’m investigating how to get my TC StudioKonnekt work under Linux.