If you are truly that unattached, go to the one that can give you the quickest class date, shortest time on reserve, and will fly your butt off. It used to be to get hired at a major you needed 1000 TPIC. With an otherwise clean record, 500 of 121 SIC puts you in the zone now. If the regional can hold together that long you can probably get a ULCC job and get a second type and some heavier flying that will make you competitive anywhere if you don’t like it there.

But futz around for 3-4 years in the regionals - assuming they survive - and you’ll be way behind those who moved quicker for the rest of your career. And try to go to one unlikely to crash before you get at least 500 SIC. That probably excludes flying 50 pax aircraft.