Upgrade Suggestions for Turntable/Cartridge/Preamp chain

Thank you @ elliottbnewcombjr for the detailed response.  I definitely was underwhelmed by the stereo separation of the VM-95ML.  Now I understand why. (have to pay more attention to ALL the specs next time). I prefer it's overall sound signature to the OM-20 other than the limited stereo separation.  

I am very handy and have no problem doing cartridge alignment tasks. I have a mirrored alignment protractor along with some of the PDF printable protractors, in particular a Baerwald arc protractor that I have utilized so far. 

Obtaining a headshell with azimuth adjustment will definitely open up new possibilities. Reading up on cartridge and stylus alignment a while back was quite informative and underscored to me how critical this task is to good playback.

The rest of my system is rather underwhelming at this point. The house has three systems at the moment with the turntable in the office system for now as it is the only space that has room for the turntable and is also convenient for ripping vinyl to FLAC.

Office System:
Teac AI-301DA Integrated Amp
Monitor Audio Bronze 2 Bookshelf Speakers
Polk PSW-111 8" Subwoofer
Technics SL-3300 Turntable with Audio Technica VM95ML cart
Rega Phono Mini A2D phono preamp and USB A to D.
Synology NAS with content for music streaming
Sonos Connect and a PC for streaming content.

Living Room System:
Yamaha TR-6750 Receiver
Sonus Faber Concerto Speakers and Solo center plus Minimus 7's as rear surrounds : )
Nvidia ShieldTV Streaming Box

Den System:
KEF Q100 Speakers
Sony STR-DE835 Receiver
Nvidia ShieldTV streaming box

Out in the garage are a few audio related projects that have been on the back burner for far too long.  I am building from scratch a tube preamp and a pair of monoblock tube amps to drive the Sonus Fabers.  Also a rebuild of my much loved center of my first real system a Pioneer receiver.

On the workbench in the garage:
Pioneer SX-750 receiver awaiting rebuild (original to me)
Infinity Qb 3 way speakers awaiting rebuild (original to me)
Super Compact 150 Monoblock Tube Amps (building two from scratch per Bruce Rozenblit design)
Grounded Grid Preamp (building from scratch per Bruce Rozenblit design)

I'd be interested in what amp and speakers you're running, too. But based on what you listed, I'd start with upgrading the TT. The carts are decent enough. There's a point of diminishing returns when you put a high-quality cart on a so-so deck. Spend on a quality TT now that future higher-quality carts will benefit from.

Actually, with $1,500 I'd be apt to just get a fully serviced Technics SL-1200 MK2, and you would still have plenty leftover to stick a killer cart on it...like a Nagaoka MP-200, Hana EH or Benz Micro Silver. Then you're done with it...for now :)

What fun you will have.

I would keep that TT and Tonearm until after other upgrades were complete, it must be fun to use.

I would keep the existing headshell and cartridge and use it specifically for recordings that are 'too wide'. the cartridge is only 23db channel separation, and it's channel balance is 1.5db. It wants tracking at 2.0 grams, a bit more than I prefer, but not heavy by any means.

It would have been best for recordings like these:

https://forum.audiogon.com/discussions/2-wonderful-stereo-lp-s-rescued-by-mono-mode-and-balance

next: an additional headshell that allows azimuth adjustment

https://www.ebay.com/itm/293416434592?hash=item4450fb7ba0:g:fWQAAOSwq4VeXaps

next a MM cartridge with both wider channel separation and tighter channel balance, you will enjoy better imaging for all but the 'too wide' ones. this one sep 30db; bal 1db, also tracks 2.0g.

https://www.audio-technica.com/en-us/cartridges/type/moving-magnet/vm750sh 

next: how are your cartridge/arm alignment skills??? you need a few simple inexpensive tools and some practice.

for ANY TT, proper alignment of a cartridge, especially one with an advanced stylus shape, is more important than the very finest jeweled ...

next: try a different MM phono stage, perhaps tubes. when it comes to phono stage, I avoid 'better' and go for 'preferable'. always have return options. we cannot measure preferable, we just know when we hear it.

for MC cartridges, I am an advocate of finding a wonderful sounding MM phono stage FIRST, and using a separate SUT for MC which needs it's signal strength boosted to use that preferred MM phono stage. 

The IPT RigB metal body for the VM95 is getting high praise. Worth looking into for fairly low cost.

Don’t know what’s in the rest of your system, but on the other hand, I went from a very good VM95SH that's reasonably similar to the ML, to a Nagaoka MP500 and am loving the lush midrange clarity and musicality, extraordinary separation and soundstage, as well as pristine refined treble. Not low cost by any means, but is a very special cart. The MP200 or 300 would also be worthy of consideration.

Technics SL-1200GR