The problem is not the level of power. The problem is that it's being applied
backwards.
There is no reason to believe that the writers considered the thing on Professor Paradox's arm any more than a simple time travel device back when he called Celestialsapiens "the universe's greatest power." That line was written that way because they probably had not yet considered making the Chrono Navigator into a multiverse devistating super weapon. It's kind of like how the DC character
Thunderbolt helped
fight the Anti-Monitor in Crisis on Infinite Earths. Thunderbolt is
explicitly a 5th dimensional imp, so that should make the Anti-Monitor 5 dimensional as well, right? He tanked hits from a 5 dimensional character! Well no, because Thunderblot was not revealed to be a 5th dimensional imp
until years later, and we have no evidence that was the original intention behind his character.
Greenshifter's comment is the first to provide any evidence that the writers might have been planning to reveal the Chrono Navigator as multiversal from the beginning. And I don't know the exact scene he's referencing, but if the full quote supports his point, then I'd be happy to concede my stance.
Similarly, Andy argues that my metatextual approach simply is not a standard or accepted analysis method on this site, which is fine. I'm new here. Everybody has a different way of doing things, and it's quite possible that I just haven't adapted to the rules yet. I'm fine to concede on those grounds as well.
But for the time being, I still hold that it is not reasonable to assume that the Chrono Navigator's multiversal abilities were being considered when Professor Paradox called Celestialsapiens "the universe's greatest power," as those multiversal abilities had not yet been established or likely even
conceived. Whether you accept that as substantial enough to prevent an upgrade is your own porrogative.
It is not unthinkable that the Celestialsapiens could be multiversal beings. Their universal feats seem to be done very casually. But the only evidence I've seen here seems to consistenly point to universal. Just take a look at the quotes. "The most powerful being in the universe" (X = Ben + 2), "the greatest power in the universe" (Map of Infinity), "greatest power in the universe," "the universe's greatest power" (Forge of Creation), "Celestialsapiens change the universe as often as my client changes his shirt," "Celestialsapiens change the universe all the time," "Celestialsapiens are out there changing the universe at this very moment" (Universe VS Tennyson). Every single vague quote involving "omnipotence" or their ability to "do anything" is solely within the context of universal quotes. Even the writers
seem to think Celestialsapiens are universal. This is a stark contrast to the Chrono Navigator, which is very explicitely multiversal in the only ever discussion about the extent of its abilities. "Absolute power over everything. All timelines, all alternate realities. Everything," "destroy all of time and causality itself," "dominion over all space and time," "Every time-line, every alternate reality" (Ben Again). When ambiguous statements like "all of existence" are said in
this context, it's clearly referring to the entire multiverse. It then seems like reaching to me if your only way of upgrading a repeatedly universal being is to retroactively scale it to an explicitely multiversal device by use of a fairly general quote that did not directly reference said device and was said by someone years before said device was established by the writers as multiversal. Again, it's fine if that's just not how the rules work here or if there's extra context that I'm missing, but I do not consider this a good argument at present. The final decision also isn't up to me, so take that as you will. I would personally prefer some actual multiversal feats, some multiversal statements, or even a more direct comparison to the Chrono Navigator.