if you had this system, what would you do to make it sound the best you can

Do the free stuff first.  Set up the system properly.in your room.  Location of speakers are equipment makes a big difference. 

Speaker are no more important than anything else in the system.  They should be the last thing replaced.  The most important link is your source.  Whatever gets the music off the media is priority.  Speakers will never add back what was lost at the source. 

Priorities should go:\

1)  Cartridge

2)  Arm

3)  Turntable

4)  Phono stage

5)  Preamp

6)  Amp

7)  Speakers

always buy the best cables you can afford or justify.  Don't waste money on highend speakers when the rest of your gear is not up to that standard.  Garbage in garbage out.

Welcome and best with all the advice.  You might want to establish a budget.  How much do you want to spend on this first iteration of upgrades?  Maybe make the rounds and listen some decent systems.  Lastly, you will go much further dumping the analog and upgrading on the digital side.  Don’t discount room acoustics, speaker and listener placement.

Many things need to go .being a ex Audio dealer any products you have are sub standard ,the Panamax good for a printer or Pc , try a Puritan line conditioner

that is not current limiting , a EQ degrades the sound inside pure crap,parts quality

buy a Quality dac Depending on budget.

comparisons on many areas and levels .