What are the most balanced relatively neutral cartridges at each price level ?

Save your money. Look at the Audio-Technica AT-VM95ML or the Goldring E4. Fabulous sound from both. Not fancy but they do the job really nicely.

I consider the Dynavector house sound to be neutral, and I moved from a 10X5 to 20XH, to a XX-2.  Not too warm, not too bright.  

Frankly I don’t see anything wrong with using digital references.  Master dubs on the other hand I have a problem with.  Where did they come from?  What mics were used?  How many mics?  What kind of a mixing console?  Who was the engineer?  It is hard to know some times.  Might be good, might not

I’m not understanding this. How or why is "What mics were used?", "mixing console?", etc. an issue for tape recorded music but not for digital recording?  (Whether from original digital recording or digital copy of analog recording.) 

Under $500? Ortofon 2m Bronze or Hana EH.

Under $1000? Ortofon 2m Black or Hana SL or SH Mk 2. Also, The Hana S Mk 2 carts are probably the best overall value available. 

Under $2000? Hana SL or SH, 

Over $2000? Hana Umami Blue ($2500) or Red ($3950)

Over $4000? Honestly, not sure why you'd need to go there.

At level 2, $1-3K, I have a Koetsu

At level 4, $5K+, I have a Koetsu Onyx and a Koetsu Leopard. 
 

Koetsu is not known for its neutrality, but of the three, the Leopard is most neutral.