Thanks, @Zurlingo-3D and @debonr - I tried 5 infills types, including gyroid, adaptive cubic, grid, linear and hex. It’s safe to say that infill is not the problem.
Just as I was re-slicing the model with Orca Slicer, I realized that I was printing with 0.12 layer height setting. Since I didn’t need the extra quality, ran it at 0.20 and it printed great. Printed the three copies I needed on as many filaments, all printed great (all using adaptive cubic infill).
I’d love to find out what else could be the problem (lower layer height sounds as a weird reason to solely produce the grinding), but I have other projects to move to, so I’ll move on. Thanks all for chipping in!
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