This'd fit better for another topic, but there was a now-deleted interview from 2019 with Sejoon Kim (one of the film's animation directors) and what he said about working with Khara is that it definitely is tough, but no tougher than anywhere else and pays better with more or less the same workload because he thinks Anno knows how it feels to work under poor management from Gainax, so who knows.
There's also the fact many recruitees from 10 years ago (3.0's production) are still staying and now on higher positions like Yusuke Matsui who went from being a CG Animator in 3.0 to CG Animation Director in 3.0+1.0 and Shuichi Iseki who was an in-betweener back in 3.0 to animation director in 3.0+1.0, so there's a sense of progression for the employees. Rebuild also doesn't have a production committee so Khara is in full control of licensing rights and by that, the revenue goes directly to them too. That's how they've been sustaining themselves for 15 years.
Breathe the air, take in the feeling of peace and harmony.