Wisdom? Who knows? A second opinion? Sure.
Regional 121 hours give you a better shot at many majors but AA mainline isn’t going to be hiring for a long time and when they are they’ll be hiring as few WO guys as possible to try to keep their feeders full. But you are also going to be stuck as an FO for a long time where you are, and not getting TPIC. And TPIC tends to be the price of admission at most majors, and certainly at the Big Four.
Truthfully, unless you aren’t hirable at a major except by flow or have your heart set on the Big Four, I’d put in apps to the two majors that are hiring right now (F9 & NK), maybe Breeze and Allegiant as well, and take the Wheels Up job. Make more money, see the world, get another type, maybe start getting TPIC sooner.
Right now it seems like SWA, and the ULCCs are going to lead this recovery, probably by at least two years. Will you make more money flying for the Big Three over the course of your career? Possibly. Over the next decade? Doubtful.