Variable
Inspired
Fastest way to fix USB issues on Big Sur for me is to unplug the Axe USB on the Mac's port and then plug it back in. MacOS gets confused and that forces it to reload core-audio for the Axe (this is even if you see the Axe as an available devices). Doesn't always happen after power cycling the Axe, but frequently enough. Unplugging it and plugging it back in solves it every time for me.