I don't know of any operator in the US that will sponsor a foreign pilot, but that's only because I'm not looking to move to the US. I've heard there are some that do, but I'll let other, more knowledgeable people on that chime in.
What I will say about the EB-3 visa, knowledgeable only because friends of mine are doing it, is that you have to demonstrate that you've done something above and beyond the average pilot with your career. A 64-year-old pilot has possibly flown multiple types, been involved in training and checking at the airline level, and may have done a few rounds through standards or management positions. The 28-year-old pilot has likely done none of that, with maybe one or two type ratings and a few thousand hours (if that), with maybe some ab initio instructing. It is that difference in experience that makes all the difference. Remember: the government doesn't care what you will do for an individual company, but rather what you can bring to the industry as a whole. The company cares that the 64-year-old won't be able to sit left seat for long, but that's not the government's concern with respect to the visa.
I'd also suggest that you consider taking a right seat spot and not going direct left seat. When I was in a standards position, I trained and coached a lot of Direct Entry Captains, and the most common response from them after the 6-month mark was that they wish they had sat right seat for six months and after a year they wished they had sat right seat for a year if only to get comfortable with the way the company operates the airplane. And this was from guys with 20 years of heavy international jet time coming back to turboprops and medium jets who I felt were giving me line indoctrination, not the other way around. But, if it's an option and you think you can make it work, go for it. Just know you'll be sitting at the bottom of the seniority list until the FO one number ahead of you upgrades. It could be a long wait on reserve, out of base, doing the commuting thing. Lots of guys I know hold off on the upgrade just so they don't have to hold reserve. So I suppose all I'm saying is to keep your options open.