I have a couple of websites that I go to that do not like working in Firefox but work just fine in Chromium browsers.

The worst offender is Microsoft admin 365. It will open, and it will work, but if you edit a user and save your edits you can't click on the back button inside of the window that has popped up for editing and instead you have to close the entire section and reopen it to go back to the main screen.

Aside from that, for netdocs you have to open the local host port of your netdocs app in firefox (https://localhost:(port number)) and approve to bypass the security restrictions in order for netdocs to work.

There are a handful of another apps with similar issues and most of them are from software vendors that I have to use for work.

There's one that I can't mention because it would dox me that if you don't use it in Chrome it simply does not work because the JavaScript that they use for generating the app checks to see if you are in a Chrome browser and straight up fails if the user agent does not return Chrome.

I can work around that for myself but I can't work around that for all 17,000 of our employees, and since the entire business runs on this application then we are locked in.