From what I've experienced with my extension, every update has to go through a review process. Firefox is pretty fast, chrome takes a few days and edge takes a while (opera hasn't finished reviewing my first version, so I stopped trying with them).

The only time I failed a review was early on when my build script choked and I submitted an empty file to Chrome (whoops). So I can't really tell how good those reviews are, but I'm not planning on testing them. I just know that they exist