If anyone’s interested, I’ve been working on a plugin for automatic adaptive pure intonation, which can make things like microtonal modulations relatively easy to do! Hoping to release publicly before the end of the year.
https://www.dmitrivolkov.com/projects/pivotuner/
I use the plugin at 1:56 in this thing in order to modulate up about a quarter tone for the end (it's otherwise in 12edo)