When you killed everyone in a coup

I didn‘t kill „everybody“. I killed the king, his family and his guards and maybe his ministers or generals

you are by definition a new military

No, I am a member of one of many militias

all your friends who are running around with rifles trying to do a coup are in it for power

Not all of them, but I understand what you mean

for everyone bright eyed idealist who will immediately relinquish his absolute authority that he just won by fighting a civil war, there will be 10 people who fought in civil war to get this absolute authority.

Yes. Thats how war works.

both technologies and situations are different now

Exactly