As a friend of mine said:
Some really cool panels here.
If this is it, Big Mom being defeated by those two is lame. They don't have interesting plotlines to do with her (Law wanting to uncover history and her hiding history is fake as fuck). There's no interesting connection or dynamic to it. It feels like a victory borne of "Big Mom needs to be taken down by someone, and uh these two are supposed to be Luffy's rivals, or at least equals-ish" and if that's really supposed to justify it then Oda should have written a plotline connecting them more before this. Could have put Law in WCI and made it so he developed some kind of vendetta. Could have actually made Big Mom a bigger part of what happened to Kid during the timeskip.
Furthermore, I think that "Law and Kid were also powering up, we just didn't see it, that's why they're this strong" is a lame justification because would it not have been obviously cooler if we saw how they powered up? Like yeah, Straw Hats pull powerups out of nowhere during fights too, but they still get some kind of character moment of realizing they need to be stronger, whereas this is being framed as "Yeah Law and Kid could already do this." I want to see what powerups they had offscreen.
I do think there were some cool aspects. Law extending his blade all the way to the ground and doing some shockwave through it doesn't really make sense (as though his powers usually do anyway with this kind of thing) but it's cool as heck anyway. Big Mom showed off some awesome moves; I wish the fight was longer and made her more of a raid boss but we did get some big moves; it feels like we saw the finale of her soul powers and what she can do with them.
The absolute biggest chad thing the story could do would be to make her get up after this, to show yeah, the emperors are fucking strong, they're a big deal. But I'm not getting my hopes up.