Tried this in the past, indeed hard to do, and, very heavy on cash investment, don't even think about bootstrapping it, crowdfunding might be the only way moving forward unless you somehow received huge investment.

Most important thing is "ecosystem" to me, i.e. the logistics of ICs, PCB factories, upstream and downstream vendors, etc are all in the same place or city, I don't see anywhere in US that provides this yet.

I went to Shenzhen instead, which has everything a hardware startup dreamed of, COVID kind of screwed it up for me though, back to software stuff.