Okay looks like your format spec should look something like 'bv*[ext=mp4][vcodec!^=av01]+ba[ext=m4a]/b[ext=mp4][vcodec!^=av01]'. Single quotes needed to keep shell expansion from fighting me, not sure if that will be an issue for you. You may have intended this, but the extension restriction does mean that you’ll sometimes skip “better” formats like VP9 if they are webms or something, and you can specify an output mux if that is what you are trying to achieve.

I think you would want to include [vcodec!=av1] somewhere in your format specifications. Let me try it and see.

No particular experience with the VPN issue so feel free to completely ignore this idea, but if you do have to stick with something resembling your current solution it could make sense to put it in a VM or container so that the process of rebuilding it is not so burdensome.