I never have any real issues with Firefox, and when I do I simply don't use that site. I have my girlfriend and mother using Firefox as main browser on desktop and mobile, with uBlock Origin and they've never complained.

I did have issues during an interview in Microsoft Teams refusing to play my video. "Your browser is not supported", yeah fuck you it's not supported. I explain why, ask if we can switch to Hangouts and send a link.

Works fine, if more people had the balls to do the same we wouldn't be in this situation today. It's our duty to educate people instead of conforming to the path of least resistance.