I'll just put a blunt statement out there.
I have seen current day "endeavor" over the last decade. Through mergers, leading contract, bankruptcy, bad contract, chopping block, street captains, decade upgrades. Right now, things are good and designed to be even better. In taking a "birds eye" view, if I was wanting to get into the 121 business for a career in the airlines, it would be an easy decision for endeavor. My ticket out is punched and working with new hires in the sims, but when I hear the logic of the new hires, I can't help but agree with them.
The airline business is only consistent in 1 metric, things work up, then fall apart, just to be rebuilt. Based on who owns us, what is here, what is available, and a long term viewpoint, endeavor wins. Plus, they pay the most.
Call it opinion, but run the numbers. Upgrades are happening quickly, more planes arriving, folks are leaving to DL, and new hires are given a path to DL. That's where the industry is going, although some are slow on the uptake. Others understand it, but are in contracts that are cost prohibitive to attract talent. DL owns endeavor and is paying to play for seamless operation from a regional to DL mainline.
DL wants us to hire 60/mo, and are paying so, with movement as the new bonus. Upgrade will be under 3 years, 2ish years if you are willing to go anywhere for upgrade. 6 months ago, I was a downgraded 900 FO by seniority. Now I'd be a 900 line holder of I was bidding. Working in training is a different, yet a fun and challenging, animal.
It should be a simple decision, yet folks want to use the idea of "what if" instead of "this is happening". Take what is going on at face value, look at where you want to go, and look at what is available. It's not a sales pitch, just run the Numbers.