Help with Cartridge choice

If I understand you correctly you are planning on upgrading the cartridge first, then the turntable. I would reverse that. Turntable first.

I have been lucky with cartridges after my first budget ones. But it has required an enormous amount of research. For me, the starting point has been the sound of my existing cartridge… was it natural enough, detailed enough, tonal balance? If my existing one is bordering on too much detail (so it is bringing in too much surface noice)… or too warm with not enough detail… then this points to a direction… or if it is perfect, then higher level cartridge with the same characteristic. It also must be appropriate for your tone arm.

So, as a starting point, read every professional review on your existing cartridge, and then on cartridges in your price range. You have to carefully evaluate the nuances of the sound description and of the equipment being used by the reviewer… it’s not easy. But, the right cartridge is not an absolute, it can be different for every user and associated collection of equipment.

OP. You are likely in for a real treat. I remember moving from budget stuff to a quality analog rig. It was truly jaw dropping… all the surface noice disappeared… it just wasn’t diminished… completely gone. The bass when up to slap me in my face… the soundstage expanded beyond my speakers. The step up from real budget or mid-fi gear is simply transformative. The VPI 21 and a well chosen cartridge with the Zesto should be a completely overwhelming change. Likely to shame your digital end.