By single flywheel motor I assume you mean the motor and flywheel together in a single case. I would not give up mine as I have always found that anything making the speed of the the TT more constant can generally be heard as an improvement. Are you concerned about its size?
In any event you can experiment by detaching the flywheel and arranging the motor temporarily so that the TT is run from the motor alone. Play some solo piano music before and after the change.
I can’t really advise on available arms. It was a long while ago that I switched a 12" metal arm tub for a 12" 3d arm tube and was happy with the result and was able to sell the old one. Then I went to the 2nd pivot (with a ruby point) and was even happier. An advantage was cost as I mounted the arm on the same base. Had to get a new spike though, one without the damping well. You might get that thrown in with the deal. I did.