Interesting idea on TTS. I love getting ideas. Lots of what is built into this app is based on the ideas from our users.
Yeah I am avoiding more UI configuration mostly because it requires so much testing across different devices and we are so small. If it is config that is the same across all devices and does not affect the core layout then it is not so bad. I know many users would like Garmin or Wahoo like screen editor but we would need to be much bigger with bigger test team at the minimum.
We have this feature that shows interval comments, and we could just use that (maybe improve them visually at the same time) that is just a temporary popup. That would be easiest, I would even say easy.