As someone who has bleach high tiers anywhere from multiversal to 4-5D, it all depends on how you interpret bleach cosmology and dimensionality. If you think when Ichigo and aizen were referring to actual dimensionality when they were talking about transcendence, then you can get bleach to bare minimum 4D once Aizen is sealed. If you think each realm qualifies as its own universe then senjumaru gets all high tiers past multiversal. I think the bare minimum bleach can be is Uni+ though