Something very similar happened to me.
I absolutely LOVED my job for four years. I had a male counterpart in another region that had the same role as me, but just worked with his own region. I thought he was terrible at his job and clients would complain about him to me and ask why he was doing so little and I was doing so much. They actually would ask me to give him pointers.
He was promoted and became my manager, and I went from loving that job to being absolutely miserable.
He continuously told me my results didn't matter. He was getting zero results and I was outshining him in every single campaign. It was so obvious. Clients continued to complain about him. He was both awful at his job and an awful manager.
Out of nowhere, he put me on a Performance Improvement Plan that was genuinely filled with lies. I had paper trails for every single thing on there proving they were wrong. He made me a nervous wreck about everything. He made it sound like "everyone" was complaining about me.
One day, he "accidentally" forwards me an email in which he was encouraging a coworker to badmouth me (as in, prying "feedback" from him.)
My manager wrote that, "She is trying too hard."
He put me on a PIP.
He said I would be fired if I didn't improve.
And then he "accidentally" forwards me an email saying I am trying too hard.
I was LIVID.
I responded and said, "Was I supposed to see this?"
My manager responded that it was nothing personal. (Funny, it seemed very personal to me.)
I went to HR and raised Hell and they didn't care.
I took the next job offer I got, and have now been there four years and have been promoted three times.
I make 3x what I was making at the old job.
Nobody has ever once told me here that my results don't matter. I am respected, appreciated and celebrated here.
Please get out of that job. You deserve better.