I'm currently interviewing, but I'm so exhausted that I am seriously considering to quit without having a new job. When I look at that legacy mess and try to make sense of it, my monkey brain just says "no".

Don’. Better getting fired and collect that unemployment rather than quitting

Totally understand this, feel this all the time only to realise how poor I actually am and just think "don't try as hard next day, take it easy, if manager grills you for being late, what's the worst that can happen? Free severance pay?"