Thanks for posting this. The mere fact that you're asking here tells me that you've already thought about this more than most would. I agree with others saying

Thanks for posting this. The mere fact that you're asking here tells me that you've already thought about this more than most would. I agree with others saying based on your details it's completely the right thing to go after 6 months and seeing no desire to change how things are done. Normally I would say that this is a problem owned by the senior devs already there. In this new age of "Remote first company", I suspect that it has more to do with the way the company was expected to operate from the outset. The leadership didn't hire senior enough people to tell the difference between good/bad and what was going to cost them for the duration of the company. It doesn't help that the devs are doubling-down on it though--doing what they're paid to do is another way of looking at that. It sucks, leave. A good thought experiment is if you were (one of) the first senior dev hired, would leadership be happy with how long you were taking to make good choices and do things in an efficient (in the long term) way? If the answer is "no", then the company was doomed before any devs were hired. Another question is how do we find out before joining? "I'll sign an NDA, show me your code"? If I'm seriously considering joining I'd like to spend a half (or full) day pairing with someone senior at the company on real development in-progress.