Is it possible to set up multiple wake up interrupts on STM32. ? How to manage multiple sensor reading intervals?
This is a trivial software problem. You keep "time to next wake-up" per each sensor. On every wake-up you subtract elapsed time from every value, measure sensors that reached zero (and re-initialize their counters with corresponding sampling periods) and at the same time find the smallest value of the rest. Setup your timer to wake-up after this smallest period and activate sleep again.

You only need one wake-up source for this to work. It can be RTC alarm, low-power timer or even WDT timer, depending on what is available on your MCU in chosen sleep mode. This method will work even if longest possible sleep period is shorter than smallest required delay. In this case you simply subtract elapsed time without polling any sensors and go into next sleep period immediately.