Biggest improvement after being sure the preamp load matches the cartridge, is to put it in a sealed lined box suspended. Reducing acoustic feedback does wonders. Sitting on a shelf between the speakers is about the worst place for it.
Speed control helps as my friends who are musicians claim most LPs are not cut at the correct speed and pitch is off. I am not a musician so I can't tell if an A is 440 or 441. Some can.
Back in the day, I ran a Thorens I modified with a Grace arm. Platter was filled with plumbers putty. Sorbothane mat. We compared it to a friends SP-12 and a SOTA. Once set up, no difference. The Linn was a pain to get set correctly. I hope new tables are better. I think the mass I added to the Thorens really helped in speed consistency. Oh, I put the pre-amp in the base of the Thorens so I could reduce noise and control the impedances better. My own, parallel FETs diff input, se output.
Tables do seem to be a place where we go from cheap ( and sound like it) to half decent but cheap, to very good, well engineered but affordable, to silly ego mega-buck that usually sit out to impress friends and are never played.
Yea, a lot of early CDs were transcribed with first generation 14-bit Sony's and the engineers had not learned the medium yet. But, I would rather have less than perfect sound than to miss all that great music.