I’m not a big fan of mounting at the axle because any time you remove the rear wheel, the rack gets involved. If you go with the p-clamps at the seat stays you can flip the bike and pull the wheel and the rack is not involved. Though the axle solution does look cleaner.
Years ago I tried a axle mount solution from Axiom (can’t recall for sure) and it was a pain in the butt.
-Kedosto