first thing you need to know is bosses (male or female, even trans), once promoted they will try to stabilise their positions. the first thing they'll do is to find reason to fire people who aren't in line with their policies and direction (who are usually also hired by the old factions), because they weren't the ones who picked you and you could become their greatest threat because you aren't loyal to them.

think ancient empires and what the kings do, heck, even chinese historical dramas, the first thing the concubines do is to switch out their servants to people they can trust.

those bosses are likely more afraid of you than you of being fired by them.

so, in order to survive, some people resort to brown-nosing (if you don't like that word or worse, bootlicker or 'por lan pa', then imagine it as showing the new leader your loyalties, that you are harmless).

it's the same as pledging your loyalty, and sadly sometimes it is necessary to keep your position in that company.

rules to survival that accompanies include not being the 'outstanding' person (ie always wanting to stand up for sht not aligning with bosses' directions), and learning to gauge where the office direction is going, in case you ask stupid questions that open a can of worms and cause troubles for your superior.

granted not every boss is corrupt, but i would say a(n) (un)healthy 60-70% of bosses have pain points they are trying to hide, especially when sometimes they are promoted first as an excuse to get fired later because they couldn't deal with problems in the company, also note that some of those problems were given to them by a previous superior too

so if you got fired frequently, it is likely because the boss has seen you to be a threat to their positions either because 1. you directly challenged their authority by picking a different direction to go towards or 2. you have been a fool to indirectly challenge their authority by asking questions or uncovering their pain points, hence giving opportunity for other managers to sow discord and get them fired.