You mentioned that it is a belt drive turntable Without knowing the turntable, I can’t know if this is a possibility. Rather than trying an outboard arm pod, would it be possible to try an outboard motor with a long thread around the platter? You might be able to get a really good motor and controller separate and isolated from the turntable giving you an even better final result.
it’s hard to imagine what a solution might be without knowing the design of the turntable and how the motor is connected to the plinth.
3 integrated, completely insulated AC-motors
Seems the manufacturer needs to do some more design work. It's now silent at 33 but not at 45rpm. 45 rpm is 37% faster speed x 3 motors should have been tested by the manufacturer one would think
Not sure is 230 volts 50hz vs 120 volts 60 hz for USA adds any potential issues