I worked, in the US as a US citizen, for a foreign company. Obtaining work visas for internal moves required legal work and a lot of HR angst to move Canadians across the border. They were reluctant sponsors of work visas. There is no way a US mainline carrier will sponsor a non-US pilot for a work visa. Try marriage and it still isn’t easy, then go to a regional, maybe in 2-3 years, optimistically you’ll be competitive.

GF