What is the best system one can make under $5000

"Pair of KH Neumann 310".

That’s 5 grand right there.

Dumb question: What is the difference between a monitor and a speaker/loudspeaker? Is it the same as a powered speaker?

Schitt saga - preamp
Schitt vidar - amp
Schitt modi multibit - DAC
Ohm walsh 2000 mains
Rythmik F18 sealed servo sub
Bluejeans cables
Chromecast audio - digital source, run fiber out to the modi

Can mono block the vidars and get balanced connections if you buy a second one (would need to upgrade to the Schitt Freya preamp, however)

Since you're looking for fairly neutral and uncolored sound, there's a pair of Revel F206 here for $2500 and a Hegel H160 (that has all the connections you're looking for) for $1400 that will likely sound fantastic and leave you with another $1100 for whatever else.  Best of luck. 

KEF LS50 Wireless ~$2500

Technics SL1200GR ~$1700

$800 left for a decent phono preamp

•  Buy all from same dealer and maybe they'll throw in a good TT cartridge
  

or ask for typical 10 to 15% discount and put it toward a cart like the Ortofon 2M Bronze 

Such a system would likely embarrass some costing 3x more.

Use whatever cables you can get your hands on in addition to the manufacturer supplied cables. Best Buy RocketFish works perfectly fine. Don't waste money on esoteric cables or power conditioning, at least not at the start.