It is pretty hard to rip Blu Rays, from my surface level understanding only one piece of software supports it (MakeMKV), and only certain Blu Ray drives with specific versions of firmware support it.
mpv can be convinced to rip most blurays, but getting the requisite magic files can be a bit of a trip. You're looking for the latest "KEYDB.cfg".
There's also still a chunk of blurays that it just won't rip because they're too sophisticated, although shocking few releases seem to be releasing those. (Must be a lot more expensive to make them.) You also run the risk that if you're not careful about what you put in your drive, you can have the latest Bluray disk revoke your drive simply by it spinning up and doing the initial read before you even ask for anything, from what I gather. I'm not sure if this is a current risk, but it's always changing.
I've also found there's some confusion about what constitutes a 'track number'. DVD only has one, Bluray seems to have two. Most releases keep both in sync, but not all of them. The STTNG Blurays were a bit tricky to get the right shows off in the right order.
