I have the app installed from the Google Play store without any issue. Mostly uploading my phone photos. Could that means if I try to upload others files than media it will not work? Or Nextcloud isn’t updated on the Google Play store anymore?

Yeah you’re right, it guess the battery health based on prolonged usage. I’m not sure what you are looking for exists in stock Android ROM. It’s very possible that info is restricted to the system, so apps cannot access it.

Let us know if you find something, I would be very interested.

Try Accubattery, it’s pretty good for the health check of the battery.