[Jugurtha]

Start looking for another job. Systematically. Consistently. Do it after work.

Do your work to the best of your ability. Do not engage in debates. Do as you are told. Get things in writing. Report to your manager and manager only and do what they tell you to do in writing. Nothing more, nothing less.

Disengage.

This is not just one person. Your manager appears to have failed. That company will go down soon or will stop growing as it churns people out like cannon fodder.

One option is to put your manager in front of their responsibility by involving the proper people, their manager and HR. Being fired is a possible and likely outcome and you stated that you cannot afford that, so start looking elsewhere. Unless you deeply care about this company, as in, you want to build it and take it to the next level, go somewhere else. Life is too short to work with people you dread talking with.