Exactly. Card acceptance is near 100% in the US and almost every ATM charges fees. There’s no reason a tourist would need to touch a single cent. I go to the US every year and never touch cash, and when I lived in the US I only used cash very, very rarely. This simply is a non-issue for the US. Living in the US, I needed well under $250 (approximate conversion of £200) cash a year. Usually closer to $50. In a year, living there.
OP - maybe one of the nice people here like @HughWells or @RichardR could make your Monzo dreams come true? 