how to permanently synchronize alarm scheds from RTC?

Projects General Guidance
2

Take a look at the time library example TimeRTC. It demonstrates how to synchronize the Arduino clock with the RTC. The key function is setSynchProvider, but the argument will need to be adapted for your RTC library command which returns the "unix time".

setSyncProvider(RTC.get);
//the argument is library dependent
//RTC.get is for DS1307.h and similar libs like Christensen DS3232.h

For other libraries, you will have something like this where synchProvider is a function which returns a uint32_t

uint32_t syncProvider()
{
  //code to return unix time from your library
}

setSynchProvider(synchProvider);