I'm still able to use Shush with my XLR mic (connected with UA Arrow USB-C interface). Might be worth considering that, if the Scarlett doesn't show up as an input in your sound connections.

This is really useful, thanks for posting. It makes me want to look into getting a hardware mute button myself. I didn't realize that there were foot pedal options, and that sounds really nice! I'll have to research what would work for me, though, since I am amplifying my mics to line level before sending the signal to my computers, so I want to check that a mute button would work well with that setup.

With XLR mics, do you have any problems with cell phone interference? Cell phone interference causes me lots of headaches, although my system uses several analog mixers in addition to an XLR mic, which might be making it worse. I've been able to dampen the interference somewhat with ferrite beads, but it doesn't eliminate it.

My use case is different - I'm not a podcaster, but I do have three computers and sit on conference calls a lot more than I ever did before. I recently set up some mixers in my home office to mix audio from 3 computers into one set of headphones, and splitting mic signal to 3 computers from one mic, with hardware knobs for controlling them: https://me.micahrl.com/projects/deskmx/

(If you want to hear what my cell phone interference sounds like, I embedded some audio in that page.)