Once you become known as a skilled manipulator fewer people are going to trust you and fewer people you can influence in the long run.

The very long run, perhaps.

In the shorter run of, say, 10-100 years, it isn't in the least clear to me that the advantage of being considered (accurately or not) a skilled manipulator, in terms of the willingness of powerful agents to ally with me, is fully offset (let alone overpowered) by the disadvantage of it, in terms of people being less influenceable by me. Add to that the advantages of actually being a skilled manipulator, and that's even less clear.

Admittedly, if I anticipate having a significantly longer effective lifespan than that, I may prefer not to risk it.