https://github.com/black7375/Firefox-UI-Fix

This won't change your mobile experience, but on desktop this makes Firefox absolutely gorgeous. I've been using it for at least a year now and it still blows me away every time I happen to see the stock UI.

I literally don't know what people who say this mean. It looks totally modern, almost identical to the chrome and edge UIs, it's fully customizable, and there are thousands of extensions to alter the appearance in a single click, not to mention custom css styling if you want complete control.

How is the mobile app terrible? I've been using it for years with no issues, and it has many extensions that chrome on Android doesn't allow like adblocking.

The tabs in FF are great, for years now FF has been much better at handing huge accounts of passive tabs, and there are tons of extensions to provide any functionality you could want.

I guarantee you if you just install a few extensions that you like and use it for a week you won't even notice any more.