Originally posted by TheVaultDweller
I'm assuming this is only main timeline MCU and doesn't include What If characters, like Uatu, Infinity Ultron and Strange Supreme.
Wasn't Strange Supreme in Multiverse of Madness, making him part of the main timeline?
Also, there's characters like Dormammu, Ego and the Celestials in the MCU.
The thing here is that as strong and fast as the Superman are, there's still a number of MCU characters that they can't oneshot. Guys like Hulk, Thor, Kurse, Abom, Icarus, Hela, Thanos, etc.... even if we assume that they're unable to land a hit on the Supermen, the Supermen will still need a bit of time trying to take them out.
And while the Supermen are busy taking out the tankier characters, it will leave them open to magical attacks. Dr. Strange and his ilk can drag them into the mirror dimension, Wanda can start rearranging their body parts or maybe even mind control one of them, heck Thanos can just snap them out of existence if he has the IG.
Even if we assume that they're somehow able to avoid all these magical attacks and kill all these magic users, you still end up with cosmic beings that the Superman won't be able to take out. Beings like Dormammu, Ego, the Celestials, even that shadow dragon that Shang-Chi fought.
Because for all of the Supermen's powers, their offensive attacks still boil down to basically just punching and heat vision, and a lot of these cosmic characters can't be taken out with just that. Best case scenario the Supermen can hope for is a stalemate, where neither them nor the cosmic beings can take each other out.
Even if Reeve turns back time, they'll still be stuck with the same problem. Besides, Reeve can only turn back time on Earth. The MCU goes beyond just earth. That's assuming Dr. Strange doesn't already lock them into a time loop before Reeve tries to go back in time.
Most of these Supermen are stronger than Thanos by a large degree and Stranges magic didn't seem to bother him none, Scarlet With MAY be a problem but then again she's a glass cannon and how would she handle getting turned into paste from a speed blitz? Thor is their biggest physical challenge but again, he doesn't have the speed to match many of these guys, Supermen win this fight for sure but it'll be a tough one based purely on the numbers