I wonder how much time has actually passed by since Omni Man left Earth.
It’s because it looks like he’s already Monarch for quite a while on that planet, so I doubt that this is actually “our” Omni Man.

Since Seance Dog talked about multiple dimensions and the whole season is about the multiverse - and in this episode this was the only reference to it - I guess, they travelled to a different dimension where Omni Man is actually good…