It's quite short like i expected, but the overall tone seems a lot more positive in a saccharine way when compared to post MA arc OPM in the webcomic.
Z-city was destroyed to an absolute degree and Saitama is super homeless, the heroes took a beating from monsters arguably worse than in the webcomic but didn't get the actual brutal humiliation from Garou (in fact Garou barely interacted with them at all, mostly did positive things like beat High Dragon+ and Above Dragon monsters for them), actual people died (Atomic Samurai companions), but it barely seems like there was any loss with how positive this epilogue seems.
It feels kinda weird tbh, like in an even more unusual way than regular shounen logic. We got an epic fight between Garou and Saitama with heavy consequences to show us the terror of God, and absolutely everything about it was forgotten and buried without a single aftertought, even the person who knows about it seems barely affected by it, hell Genos seems even happier than before wich is a little weird. We know there's a villain out there that's even stronger than current Saitama to the point he'd fodderize his pre-amp self to oblivion and there's nothing about him on the epilogue. He was ultra active for some unknown reason and will now just seemingly go into hibernation mode until plot calls him back i guess.
I'd say the arc started great, reached a peak during while they were underground, was good during Tatsumaki vs Psykorochi, then got bloated as hell with Sage Centipede and the excess of heroes in the field (like, if you removed Amai mask literally nothing would change, and if you removed Metal bat it would change for the best,lol. Same thing with the council of the blades, wich were forgettable at best and only served to give Atomic Samurai a meh powerup that quickly fell for the powercreep.) Certain moments like Black sperm's shine were greatly diminished by Psykorochi, wich is a fair trade, but Fubuki lost her coolest moment for some jetfight and S-class ******** vs Psykos, wich was not a good trade imo. Then we reached peak again through sheer hype ala Dragon Ball Super and Saitama's funny feats, and proceeded to fall off terribly with what was imo one of the worst choices ONE has taken so far wich was retconning any consequence of the fight with time travel and then proceeding to not even leave memory behind wich would at least have happened if he used the "it was all a bad dream copout".