Then you're the same as anybody else down here. Get your license converted to a US commercial AMEL. Don't waste the effort/money on an ATP.

Most regionals will hire you and put you through all of the ATP training during new hire training. You'll need all of the aeronautical experience requirements for a US ATP, except you can get the last 25 hours of ME and total time in the sim during regional training. So you can get away with 25 hours ME and 1475 total time.

As to majors, AA owned regionals have a flow path to AA mainline. Other regionals have preferential interviews at UA and maybe DAL. For the most part you can pick your regional, so do your homework.