I ended up using MakeMKV, which allows media players like VLC to offload decryption to it via the included libmmbd, and it worked like a charm! VLC does support playback from all regions, but I needed to first switch to the appropriate one using Tools -> Preferences -> Show settings: All -> Input / Codecs -> Access modules -> Blu-ray -> Region code (there is built-in search for settings, fortunately).