The latency thing is something we cannot reproduce.
Could you please confirm that it is still there even after a factory reset?
If it's still there, the usual thing to do for diagnostics is to use MIDI monitor software and try to see if there is a significant delay between an action on the controller and new data being displayed on the screen. It would be very helpful if you could test your Sylphyo+Link using a MIDI monitor (see this article for help), ideally showing us a video of the delay.
We didn't achieve the factory reset on upgraded Sylphyo to avoid changing our user setup. This seems to have been the issue.
Adding extra MIDI parameter can add latency due to additional MIDI messages (and MIDI low baudrate), but only at the last MIDI conversion level (either on the Sylphyo USB MIDI or on the Link MIDI DIN or USB output).
It's something we're regularly thinking about, but that isn't really simple to implement, notably because the MIDI protocol makes it hard to work with, and because there are few synths out there that understand the relevant MIDI messages. Anyway, MIDI isn't designed from the ground up to allow you to play outside the 12-tone equal temperament (12-TET), so a popular approach is to let your synth or virtual instrument handle this.
You might want to look at synths or virtual instruments that are explicitly designed for this (look for terms like microtuning), like the Samplemodeling virtual instruments.
In general, they allow you to define the exact frequency (or offset from a base frequency) of each of the 12 tones (C, C#, D, D#, E, F… B) that can be sent by your MIDI controller.