Energetic Angel Ring just lets me fly for a blink and then drops me back to the ground

Can confirm this, this happens because when you start flying, it consumes energy, changing NBT, and Curios checks if item still matches, and it fails to match (NBT changed) and triggers the onUnequip function that causes you to lose flying ability.

Thanks for the report. This is probably due to an introduced check for long values. Will investigate that today.

Nevermind, I accidentally removed a check whether I haven't planned to remove it at all. Oops.

Fixed in 2.3.1. Update to it from 2.3.0 and you should be fine.