One of his many build threads, but this deals extensively with truss rod replacement and neck repair
That’s an extreme version, but just adding a washer, or maybe two, to add a little more back bend is a tried and trusted method. I had to add one to my Fender Roscoe Beck Signature when I first acquired it to reduce the amount of relief to the flatness I wanted. I had to ream out a washer I had to make it fit, like the guy says at the start of the video.