This is a feature I had on my previous headset (chinese brand), and it was absolutely great to have. I would love for my 20S to have this as well.
When turning on the headset, a voice would automatically say how much battery was left. It was really good to be constantly reminded, I basically never ran out of battery or just the one time. I've had my 20S for a few months and found myself running out of battery quite a number of times, because the battery lasts for so long that I just forget to manually check.
Whenever turning on the headset, the voice announces how much % battery is left, to the tenth percentile. Example
1. Turn on headset
2. Hear "80% battery remaining", or "20% battery remaining"
3. If the battery is low, start sending audio notifications "Battery at 20%. Please charge soon" "Battery at 10%. Please charge soon" every 5-10 minutes (with an adjustable setting option for how often, I guess?)
I hope this helps!