hi Anathema, in my very humble experience, this is caused by udev trying to configure a weird device. I had that experience with a usb winmodem, the prestige 600 series one, using the cxacru module from the soho kernel. The udev daemon will take like 10 minutes (seriously) to go ahead with that modem pluged. If you didnt, I would suggest to wait for a while before a hard reboot, if the system finally get up, you will need to find the device causing the problem and blacklist the proper module. We can think later how to configure the device properly.
Another way around would be to do a very minimal install, i.e. disable almost every device from bios, and try to boot the system, then you could enable the devices one at a time, and identify the problematic one.
A third try would be to get an older kernel, like the 5.8 standard one, and see if this one can boot.
This was my solution to the winmodem problem with udev, I hope this can help you. If one of our gurus has a better advice, please jump in
this is not a frequently problem.