Bad Batch is really that. Rebels is its own thing, unless you wrap it with Ahsoka. Rebels had a mediocre first season but after that it’s definitely top tier material.

As the other comment said, it’s not really a follow up. We do get characters from the Clone Wars appearing in it that you really need to have seen Clone Wars for but for the most part it is a seperate thing. Bad Batch is really the Clone Wars sequel, with lots of familiar characters and continuing the story of the clones as a whole