[wdewind]

To sum up:

-Your boss is emotionally aggressive, unreasonable and difficult to work with

-Basic functions of the company like payroll are not being handled properly

-The company is a few years old and has yet to achieve product market fit

-The company is a few years old and still in a position where one employee leaving will severely damage the standing of the company

One of these things, maybe, is possible to deal with (with the exception of the second one - missed payroll is completely unacceptable). All of them are absolutely not. This isn't even a question: you're wasting your time and it sounds like tolerating a lot of misery for no reason. Companies can't succeed like this.