Take note of the usage of “countless fractions”, and “unify the realm of chaos — into a single reality”. This is, verbatim, the
exact synopsis Rodin supposed Singularity was doing. Note, again, the word “unify” (統合) is there.
Singularity has explicitly stated to become one with the Chaotic Energy of the
multiverse, which would objectively puts his HDE at only a 4-D level. Singularity Chaos, again, explicitly absorbed the energy from the
parallel universes of the multiverse, which brings his attack power to the limit. It mentions he’s swollen due to the power of the World of Chaos, which, again, is synonymously used, unless you’re asserting Singularity is gaining two sources of power. The Realm of Chaos was split into countless fractions -> The Chaos World is a multi-layered structure, with countless universes -> Singularity seeks to unify the Realm of Chaos -> Rodin says correcting the multiverse by unifying them. Singularity Chaos is amped by the Chaos Energy of the Multiverse -> Singularity Definition became one with the Chaotic Energy of the Multiverse. By the transitive property, The Realm of Chaos = The Multiverse.
Note, both Singularity Chaos & Definition claim they only got power from the parallel worlds, at no time is it ever stated that they were even further amplified by Ginunungagap. If Ginnungagap truly was part of Chaos, why waste your time destroying & absorbing literally infinitesimally smaller portions of power, instead of the infinitely bigger one, then nuking the Trinity over all? It doesn’t make sense to assume it, in any context. Why isn’t it ever stated that he got Chaotic energy from Ginnungagap? It’s because he didn’t.