Sigh, it's stuff like this which really gives the franchise a bad name...
Is the franchise complex in terms of how the cosmology works? Yes(Especially with it being confirmed that not all Celestial Objects have Souls in them and there are apparently still layers of the Universe and higher beings according to Kiara Kisshioun's attempts to reach the same height as her counterpart in CCC). But again no one we know scales to any of that and the Moon Cell itself isn't Multiversal, just Multi-Dimensional(It does have like a Multi-Galaxy reach considering Kiara Sessyoin straight up ejecting the chosen Servant to a different Galaxy altogether... but the fact it couldn't contain a pure Divine Spirit and Buddha had to massively nerf himself to even be there...).
The dimension shit and otherwise is even more infuriating because it's all based on misunderstanding the shit from Imaginary Scramble and taking it 500% at it's word than a turn of phrase(To put it plainly, the Imaginary Sea is absolutely weird but it's not some gateway into higher/lower dimensions or suddenly making fiction into reality, it's basically a place where no Human Understanding of the Laws exists and you can theoretically use it to go back in time... and die doing so but hey, that's how it works).