I feel you OP. I have a Hypercube Evo that I can’t for the life of me get a leveled bed with. I’ve swapped linear rails with MGN, switched to multiple probes including a beacon that I still need to install but probably won’t help seeing this post.

I think your frame isn’t straight, there’s twist somewhere that combined with an offset from probe to nozzle means it’s impossible to remove with probing as the offset in Z between nozzle and probe changes over X and/or Y. That’s the only thing I can think of at this point.