The phono cartridge, and the phono stage may make the most sonic difference, but the TT is more important.
If the TT is not doing its job correctly (spinning at the correct speed, suppressing airborne and vibrational noise, ’sinking’ record and motor noise through the platter and plinth, etc. It won’t matter how good your cartridge and phono stage are.
And of course, the better the rest of the system is (amps, preamp, speakers, etc) the more noticeable improvements in the TT will become.