Didn't you have a managers / asst. managers that you worked with previously that you could have observed from? Should've learned from that.

3 examples:
1st case
My place last time got 1 super hotseat dept. anybody who become manager will either
1- Suffer heart attack episode
2- Request to be demoted back
3- Changed job
4- Quit
5- Combination of above
All within a year.

2nd case
Another one was a pattern of not replacing the employee that go up
(e.g. team of 1 manager + 1 jr. engineer + 1 sr. engineer,
sr. engineer promoted to manager but old position not replaced so technically as manager need to do sr. engineer job also)

3rd case
A guy who through his career pathway has already held manager jobs multiple time but
came into us as senior engineer and refused all promotion. Last I heard promoted to manager when everybody else quitting (he followed suit soon after though)

Kinda extreme examples but yeah, made me appreciate working under any manager who's not totally bad. Depends on the company also at the end of the day.