In case you have 2 or more themes on telegram you surely faced the issue where you couldn't set a theme to be used during the day(for example from 8am to 6pm) and one for the night (for the remaning time until "day"), with this app you can do exactly this!
In case you need help on how to use the app, just press the button in the bottom half of the app.
Unfortunately you must give the app root access to make it work, that's because it has to access telegram's folder and because of this, there is no way to make it work without root.
I must thank the wondeful guy that made my idea come true: @LollosoSi, thank him because he was the one who coded the whole app.
If you have no themes to choose from, you can find some good ones here: https://t.me/ABTheme