I question some of your numbers. Although, I did find on a quick google search that US was the 3rd highest grossing movie of 2019 (so far) across all genres (as you stated). Us was #26 of all horror movies at 254 million internationally. The number 1 being IT at 325 million.
IT made so much more sense to me. You have a sequel out this year, and they have a decent relationship with WB (passed houses/Scare-zone IPs and HP). Universal had the rights for it at one point for HHN28 early January. Horror made hear announced (around the same time) that they weren’t holding there event this year.
I am going to rewatch US again, but I sorta get it, I guess 254 million and a good relationship with Blumhouse. I can definitely see why people aren’t happy about it. Oh well I am not an expert, I just try to follow the logic and sometimes I just can’t... again doesn’t matter if I can follow it or not.