I would look into used:
Conrad Johnson
Audio Research
VAC
Zesto
I have upgraded my phono stages since the late 1970’s. Each time I found the phonostage holding back the sound of my tt / cartridge (Yes, this is dependent on exactly what tt / cartridge you have). It was not until I reached the Audio Research SP8 that I felt this was no longer the case.
So, my recommendation is to find a very high quality tube phono stage, and of the highest level you can afford with the brands above. Stretch you budget if you can. Your Soto is a very capable turntable and cartridges are easily upgraded. So, a really good phono stage is worth the investment.