Interesting topic, would also like to know more. Does anyone know what is the current situation with YC, do startups in U.S. hire from Europe on a B2B contract

Interesting topic, would also like to know more. Does anyone know what is the current situation with YC, do startups in U.S. hire from Europe on a B2B contract? I scoured a little through the job listings but didn't find anything worthwhile. Offtopic, but why are there so few mobile cross platform job postings in U.S., e.g. Flutter, including startups, why does everyone chase native development, especially when you are strapped for cash?