I'm back! One thing lead to another and I'm now running my X and Y axes off a basic ramps board with 8825 drivers and homemade tl smothers. Maybe also new steppers. Who can really be sure in all the confusion. I decided to try a new stepper and while I was in the printer shop I saw the RAMPS mega 2560 sandwich for $50 so I impulse bought. I set the new stepper up to try it out, then realised klipper allows me to have multiple mcus, so I tried it out. I'm still quietly stunned that running the X axis on one board and everything else on the original actually worked. The results were so good I went back and got another stepper. I'll move the z motors next.
Those are settings that make the printer sound nice and smooth, almost silent, and producing the results you see in the photo. All for ~$100. I basically got a new printer.
That print btw (post tuning, done at 0.3mm layers) got me the ultimate compliment from my daughter. "Did you print that?"