Do we have an alternative for millis() function? This is actually a follow up question to this question, so basically I'm using DS18B20 temperature sensor which requires Onewire.h library that interrupts millis() function.

Luckily i have a DS3231 RTC module which I'm using it with RTClib library, is there any way to use that module as a timer instead of millis() function?
You can use the SQW output of the module to indicate the passage of precisely 1 second. Every time it transitions from LOW to HIGH one second will have passed.

RTCs cannot give you times of higher resolution than 1 second, but they can give you that 1 second granularity to a high accuracy.