here is my summary, someone should make one of the other side and then we can create another thread
basically the only reason we accepted the 12 universes as space times was because of the rosat being an confirmed space time and being part of the universe, so it would branch along with it making accptable that other space times could be affect by time paradoxes that happen in just one of them, but as of now, the rosat was accepted as not being part of the universe anymore, that made it so that we had no reason to assume that the 12 universe multiverse in db were space times, since they were all affect by time paradoxes, this and plus the new standards for tier 2 where physical travel is impossible with 3D movement between space times and the need of having a higher 5D dimension separating the supossed space times for universes to be considered space times, in db both were disproven as the angels and the super dragon balls can travel between universes normally with flight and we have confirmed information that what is in between universes is not a higher dimension:
this one of null flower is about the neutral space that separates universes first shown in the tournament between uni 6 and 7
so basically all that makes the 12 universe not alternate spacetimes and just 3-A structures rather then low 2-C ones
edit: as pointed by executor_N0 the term most likely is referring to dimensional space, aka another dimension, but since the term for higher dimension is not used, then the end result is the same, also it is shown to just be a regular 3D cosmos with stars and planets and galaxies, which contradicts it being a higher dimension
there is also some points about how much all the different dimensions in the macrocosm are separated, but they are never said to be spatio temporal separated, they are just dimensions, not different space times, being a different dimension and having a dimensional barrier doesn't mean much doesn't mean much
there is also points about universes having different histories and events, but they are not proof of different times since the 12 universes aren't branches of eachother, they are their own indivudual places and this is no different than a country having a different history from another country
some brought points about the events from the black saga to say that different histories mean different space times, but the whole black saga talks about different timelines and not different universes that are inside said timelines
also some bring points about the time rings from each kai in each universe, but the time rings always comes from when different timelines are created, said timelines that have the 12 universes in them, so the time rings don't prove much regarding this topic
also as a bonus, Merus
refers to the Room of Spirit and Time's progression of time alternative to the outside world's as the result of
time dilation, which may imply that the Living Universe and the Room of Spirit and Time exist within the same space-time continuum, but experience the same time differently.
so since they are all affect by time paradoxes even when they are done in only a single universe, and the fact that there is no confirmation that they are space times, we should then go with the less assumption route and just make them 3-A structures