The Servant MC.
This seems to be a massive presence in asoiaf fanfiction. The over-the-top protagonist is thrust into Westeros and has his own ambitions, favorite girls, and goals before entering, and in the first five chapters he mostly meets either Ned or Daenerys and is immediately servile to them and obeys their every command without objection. The MC has the ability to destroy entire cities with his bare hands and has the personality of a doormat.
One of them I came across is the Alchemist self insert and he discovers all his powers, then joins the royal court and Cersei soon orders him to train Tommen in magic and from there everything goes downhill because the MC serves without any opposition or gain. The other was where the MC was a self-inserted dragon who serves Daenerys. He could have approached her and spoken to her as an equal from the moment he saved her, but the moment he met her, he caved in and instead of marrying her as his equal, even though he was a Dragonborn, he immediately obeyed her and followed her orders like a trained dog. and the plot boils down to the emergence of a problem, Daenerys orders it to be solved, and the MC removes the problem. He wants Daenerys, but allows her to look for other husbands while he is completely apathetic. Daenerys has not really done anything, and she has conquered everything.
Essentially, the character has the power of a god and serves the canon characters who treat him like a wish-fulfilling machine without any gratitude.
SI Friendship with the main character.
Even the villains self insert themselves end up being friends with Goku, Naruto, Jon, Ned, Percy and lose all of their personality. They later become members of their group and worship them as living deities. As if they can do no wrong.
Si killing the original protagonist is practically unheard of even when he wants to rule and the protagonist opposes him. An SI wanting to make the protagonist's life hell or eliminate them is something I've rarely seen as a regular occurrence except in Dark Wolf Shiro.