One does what one must. If that means getting a second job, do that. Many 121 pilots have their own business or a "side hustle," which runs the gamut; you name it. I've known pilots who did everything from edit porn videos to have consulting or retail businesses, to building airplanes for others, to cleaning theaters and night, doing law enforcement and other jobs, some in, some out of aviation. Whatever it takes.

My brother, in another profession, was hiring a professional, entry-level, fresh out of school. She complained that his offered salary (industry standard) wouldn't cover her loan repayments, as she owed about 500,000. He noted that it was true, but that at her level, she couldn't bring in enough revenue to match what he was paying her, and she'd have to work a second or third job, just like everyone else (just like he did). One does what one must. Whatever it takes.

Airlines not hiring? Find somewhere that is.