Read all of your options.. you list your goal in each one, moving on to a regional carrier.
The only thing standing between you and that right now are the remaining requirements of your ATPL. Right now you are in a position to get them, and while it might seem far off it could be done in less than a year.
You wage now is decent, and you are building PIC time and experience, gut it out and start preparing your resume and for airline interviews. I see no reason to change jobs, possibly move, make less money, and add more stress to your life to overcome 500 hours, no matter how "miserable" your job may seem.
Work hard, Fly smart, and keep your eye on the goal.