Were you using an AMD graphic card with HDMI 2.1 connection to a monitor/TV?
Because it happened to me that the HDMI connection stopped working after a Bazzite update, and I had to downgrade to Bazzite 44.20260802 (see the Github ticket here), which seems to be the last stable release without the problem.
My understanding is that the problem is still present in Bazzite 45.. and it likely won't be resolved until the next Kernel update (7.3.1) lands. The good news is that it just recently was updated on the unstable branch.. I haven't tested but if the issue is fixed there, I'm hopping it will be ready by the end of this month, since they normally roll updates every few weeks.