Firefox has a much worse history than Chrome when it comes to breaking extensions.
Kinda glad they disallowed the extensions that had near unfettered access to browser internals.
I'm a happy firefox user, and I'm pretty sure it was the right choice IMO, as firefox is certainly much more stable and fast now than it was before. But it was certainly a very, very rough process and left some very popular extensions broken without alternatives for months and even years before the necessary APIs were added to webextensions to bring them back.