If other chromium based browsers didn't have this issue, that would be great, but likely in time Youtube won't support browsers that don't have MV3. Probably still have some time though.
This workaround was fixed the same year in 2023 and yielded a $0 payout, on the basis that Google did not consider it a security vulnerability.
The conclusion then is that uBO (MV2) stopped working for me today after restarting my computer, I suppose.
Let them take google money for as long as it flows. You can switch to librewolf at any time if FF itself ever actually goes bad in any critical way. But there's not a lot of reason to do so until the minute that actually happens. Go ahead and take the funded work and updates as long as it exists.