So my Idea in this is Inspired by all those inner Voice things, I've seen so many of them but all of them doesn't really utilities it in a unique way because all MC's are already OP. So I thought that what if the MC only have meta knowledge and this Inner voice thingy and that he's weak, How would this MC utilities the ability of Inner voice to make people help him becoming powerful without them actually knowing he's incredibly weak.
Now it is needed that people doesn't really know that he's weak because if people just know that he's someone weak with a strange ability, they would likely just experiment on him. So for example he Joined Rias(from DXD) peerage and he's only one pawn, he will use his inner Voice and bullshit his way through by making it appears that he "intentionally" weaken himself, or make it appear that a rook or bishop is most suitable for him.
Now what set's this different from those that have a weak MC as well is that, This heroines are actually more self aware and not dumb and not just suddenly, wow so my protagonist is an incredibly disgusting being and MC kun is all so incredibly good and perfect, etc. Also make sure your MC is not an indecisive person as well, like those MC that doesn't take initiative and stay passive or dense throughout the series.