What is the best way to implement android application?

Question

Java

I would like to create an application that will mute and unmute the phone on the phone for notifications and calls from Mon to Sat) at a certain time. Mon-Fri -- 15:45, Sat -- 13:00.
Three options:
1) Through AsnycTask (not good, because it will eat up a lot of charging https://toster.ru/q/562546)
2) Through Service (Normal idea, but if I make a while loop, it will be the same , as with AsyncTask)
3) Through the BroadcastReceiver (here I did not understand how it all works. Please explain.)