Recommended a highly resolving cartridge

Not my personal favourites, but one of the top end Ortofons would probably suit your needs.

Since you are asking a general question, all I can provide is a general response:  Any Audio Technica or Ortofon cartridge would be a candidate as would a SoundSmith.  What do you presently use?  Tell us about your system, your preferences, how much do you want to spend and it will be possible to be more specific.  With regard to your arm question, I looked into this myself as I own an SL1200GAE.  I decided to buy a whole nuther TT and leave my GAE alone.  It is a splendid apparatus as is, well thought out and I just like it.  It is the one I probably use the most, the other, a VPI HW-40, out performs it, but not by as much as the cost difference would suggest.  The G tonearm is without doubt the easiest to set up of any on the market, a factor if you want to change cartridges often.  I know this because I set up a lot of turntables.  Think long and hard before giving up that arm.

New, I highly recommend boron cantilever with advanced stylus shape, and check for tight center channel balance and wide channel separation, then find some reviews that describe the quality of sound, degree of involvement others find.

I decided to risk buying used cartridges in order to get a combo of lighter tracking at 1.25g and no longer available beryllium cantilever with MicroLine stylus

I’ve been buying AT160ml, I don’t see any listed at the moment. I have them checked by Steve and Ray at VAS, so far I have gotten lucky.

this is a AT-ML150 from the same seller I successfully bought two AT160ml’s.

NOTE: there is a pause of shipping to usa, you could ask seller when they think they will resume shipping. Tarriff is 15% from Japan, billed separately by FedEx, and FedEx charged me a $4.50 disbursement fee 

https://www.ebay.com/itm/257113147950?mkevt=1&mkcid=1&mkrid=711-53200-19255-0&campid=5338381866&toolid=10001&customid=f9d8d482-a061-11f0-b91f-356436643765

stereophile review AT-ML 150

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AT160ML, and a few other bodies, have the advantage that new boron cantilever stylus can be used (note ML comes after the number, not before it)

IF you are not comfortable risking buying a used stylus, but like AT's dual magnet sound and light 1.25 tracking, you can buy a used cartridge and put a new stylus in it.

I like Boron if buying new, and I see they still sell 3 VMN Boron Stylii that fit these older AT150, AT155, AT160; AT440 bodies 

AT-VMN45xML (microlinear/nude/boron cantilever)
AT-VMN50xSH (Shibata/nude/boron cantilever)
AT-VMN60xSL (special line contact/nude/boron cantilever)

https://www.audio-technica.com/en-gb/support/which-stylus-can-i-use-to-replace-my-discontinued-model?srsltid=AfmBOoqmY8LH9JfjLmVnMHaK7edGe8NmiyTNluGGDkQDaGLFGN74nzzh