This. Every (good) job I've gotten has been from networking.

Finding good developers is hard, and companies love referrals. Those 3 senior devs that have quit likely found a job somewhere else, and that somewhere else will be hiring.

If they remember you as the passionate helpful developer who was putting in a good effort at a terrible company, they'll probably want to throw potential job opportunities your way.

And make sure they have a way to contact you, even if you are just making a connection on LinkedIn or something.