We all know how I feel about 5/3/1 and I’m not here to defend it: If it’s not working, it’s not working.
But I am curious: Have you ever tried other 5/3/1 rep schemes for bench? I’m thinking specifically 5x5/3/1, which is the basis for the 5/3/1 for Hardgainers bench (or very close to it, I think). That’s worked well for my bench in the past.
I also know my press responds better to 10x5 than to 5x10 or 5x5 supplemental—maybe something like that would work for your bench?
Just spitballing here… Definitely ditch it if it’s not the right work for your goals.