I moved away from firefox after nearly 2 decades of use, primarily for this reason.As a linux user I rely on web applications for a lot software that doesn't support linux. PWAs we're a very easy way to work around this, especially for the Microsoft ...
There is an extension which removes the tabs: https://github.com/emorris00/thunderbird-no-tabsIt works really well, obviously having this as a native option would make it easier, which is why I support adding it.
