I don’t quite understand your last post, except it seems you’ve checked the cartridge and speaker wires and the two channels are NOT out of phase. Do you understand that point?
the rest of your last post eludes my grasp. The issue I focused on is why the 47K ohm setting sounds so uniquely awful. There shouldn’t be much if any difference between 500, 825, and 1000 ohms load with your cartridge and either phono stage. Which is to say they should all sound fine and not much different from 47K ohms.