A bad boss is a free class in exactly what kind of leader you refuse to become.

Being managed badly teaches you things good management hides, because you feel every mistake from underneath. You learn what silence does to a team, what it is like to be blamed for something outside your control, how quickly people stop offering ideas. That knowledge is hard to get any other way.

Keep a running list of the specific behaviours rather than just the feeling. Write what was done and what it did to you. Years from now, when you are the one deciding, that list will be worth more than advice.