It's a difficult one to call. It's fast-paced and action-packed, which should have kids coming out of it with a lot of enthusiasm, but the thin characterisation and basic plot means word-of-mouth could go either way with mainstream adult viewers. Then there's the China factor: KotM is OTT and crazy, but is it OTT and crazy enough to make it catch fire in China, a la Aquaman and Bayformers? I'm not convinced on that front.
I think there will be a disappointing, but not disastrous, drop-off on the second weekend. Dark Phoenix will go down like the Hindenburg, so there's nothing to worry about there. MIB International is where KotM will really start to lose business on weekend 3, I think. It looks pretty mediocre, but audiences were buzzing from Comedy Thor in Endgame, and I think a lot of people will flock to Chris Hemsworth doing another humourous role, especially since they can't watch Endgame at home yet. There's not really any other big-ticket SF action coming out after that until July though (unless I'm forgetting something), so if MIB underperforms then KotM could hang in there for a while longer.
Then there's the reviews. I don't think the tepid critical reaction will damage it as much as Pacific Rim: Uprising, but they won't do it any favours.
If KotM doesn't grab China, and MIB performs well, my uninformed magic 8-ball says it might be as low as $393m. If China likes it, we might be looking at $480m. But I think the only way for it to break $500m is if China likes it and
Making up numbers is fun.