If you want to join a legacy carrier then go do it, but make sure you are young.
We had guys join big airways from my last outfit on the clapped out 767 . As they know it's 400 years to a shot at command, big airways tries to keep them interested by coming up with courses for them with names such as ' diversity in the cockpit with applied shamanism ' or some such stuff.
Not only that their rosters are sh.....not good, as there are 120,000 pilots above them on the seniority list.
Can't see the attraction if you're over 30. But then again I never had much patience .