That sucks. Do you have access to a VPN with servers in Albania or Moldova? They still don't allow ads in youtube videos.
Happened to me last month, I set proton VPN to an Albanian server and everything worked until uBlock got updated to suppress the black screen of death again. Good luck!
How long has it been since you updated uBlock? If I go about 2 weeks without restarting Firefox, they start showing up for me. A quick restart of FF and updating uBlock has always worked for me.
Let us know if it works or not.