This looks great. This is the first I have heard of ftd. It wasn't clear how to use it though. https://ftd.dev/docs/ doesn't link to the Installation, Getting started and Tutorial
You can checkout a video course: https://ftd.dev/expander/. And maybe join us on our Discord.
A language designed for authoring. But still powerful enough (one day, it’s work in progress) that you can build most UI in it.