Consider the base of the turntable and its ability to isolate the table from footfalls, vibrations from the speakers and form earthquakes (measurable in very minor increments which affect the sound that you would never know about)_ disctintly from the ability to spin the record precisely and generate no noise from it's motor.
The most expensive TTs do both in an excellent fashion, but if you are trying to optimize the investment, go with a light table like a Rega and spend a few bucks on a base (and wall shelf if needed like when you have a suspended floor). In my experience, I agree with @mijostyn that the turntable should sound like nothing so sound improvements in that would be less discernible than the arm/cartridge phono stage one you have a very good TT. Arm and cartridge need to be well matched as do the cartridge and phono stage which can make the choices complicated.
Features can play a big role in the decision. The way the power supply is plugged into Rega's P8 was the opposite versus the P5 I replaced, and the wiring directly from the arm to the end of the interconnect wiring that plugs into the phono stage was much improved. However, I upgraded the arm first from the P5 arm (RB700) to the RB880 that comes with the P8 first, and found the tonearm upgrade dramatically improved the sound. The table, not so much. Still, since I liked the new features of the P8, I don't regret getting it.