Did I write this post?
no, but I might as well have, just a few months ago.

I do not have much advice to give. What I have done, which worked due to the unique funding circumstances of my position giving me significant freedom was to initiate collaborations with other groups. I also started applying for grants without my mentor's participation. Some of my connections worked out, and I have several papers going or published without my mentor being a part of them, and I am also a key part of a hugely successful major project which has no ties to my mentor. My connections with my mentor are minimal, and shrinking.
I do not know if your contract allows this, I know I was exceedingly fortunate.