This is actually a well-known issue. Hot plugging USB 1.x devices into a Mac Pro 5,1 is broken in Big Sur. The workaround is to connect devices through a USB hub. USB 2.0 devices work fine.
@cdf Thank you very much for your help. Your advice was spot on. I got a powered USB 3 hub and now all my USB devices works from the hub.This is probably due to some device. Wake from sleep should work fine even without that kext.
Note that macOS 11.3 and higher is not recommended at all on the Mac Pro 5,1. You will eventually run into booting issues if you haven't already and perhaps even corrupt your macOS disk as well as other disks connected to your machine.
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