Which timer is being used as RTOS tick in nrf connect sdk for nrf52811

I am using nrf connect sdk 2.7.0 with nrf52811.

My application is based on nrf5-sdk V 17.1.0 but now i want to port it to nrf-conneck sdk 2.7.0.

I want to know whether k_msleep() uses internal RTC or not?

And if yes can i use k_msleep() as an alternative of rtc wakeup?

One more thing is my previous application was not based on any RTOS therefore here also i do not want to use any RTOS related functionalities that much.