The introduction of the 1500 hour rule in FAA land did result in some US Airlines offering Visas to foreign pilots that held 1500 or more hours; however the Covid situation has probably now curtailed this. This only happened in the last year or so.
Rare but did happen. I know a Polish guy who went to a regional on an H1B in early 2018.
There were some EASA approved schools based in the US that use to offer J1 visas which allowed non-US instructors to work for a limit of 12 months.
It's now an F-1 visa.
- Max 20hrs/week for as long as you like while "studying"
- Full time after that for max 1 year (CBT)
- Additional full time after that for another year after you pay $500 and jump through some hoops (OPT)
If you have 1500hrs, in theory you could go to a flight school, qualify as an instructor, and head off to the regionals for nearly 2 years. No idea about mainline.
It turned out that the pay would just about have covered for paying the rent in Florida and maybe one or two visits to Mc Donalds per week
Depends where you go. Some schools pay OK if you work your socks off