Glad you got it to work. It’s a bit of coding, but ultimately you gain more control this way. I think the new mechanism for setting presets names when saving is a good addition, so thanks for prompting that.
I wouldn’t be too concerned about the VST issue. I think this move from Steinberg is more an attempt to get the big fish to move on from VST2.4 and embrace VST3. If I was you I would release your synth anyway. I will try to get a new Windows build done in the next day or so. You probably have enough work to be doing with your new preset system in the meantime!