It’s one of Kazuyas trials for his Bankai isn’t it, because only zanpaktou can do crazy stuff like this like pulling up a separate reality. if it is then it’s really OP.
This was actually a pretty interesting scenario for Kazuya, wasn’t expecting it but it was great for him to somewhat confront the reason for his reincarnation to the bleach world, and for him to be in a what if scenario 👍 great way to spice things up a bit for kazuyas character development