For me it is with kernel 5.9 and Nvidia 450 drivers - the missing firmware for xhci error msg i get on every machine, but my nvidia (gtx970) machine just boots to a black screen. no log entries or something. but everything is fine with kernel 5.8 for me (fresh manjaro 20.1 kde install)
my intel laptop and intel nuc are working fine with kernel 5.9. seems like a nvidia problem, yes.