RTOS for GPS tracking + SAT Com

I am working on a project with the electron, where I will need to monitor 3 serial ports for sensors and sat modem.

The idea is to know when a balloon is bellow a certain altitude to use 3G data and when above to use satellite.

however all this communicate via serial and I would like to know if using the RTOS enabled my provide any benefit for not blocking the polling of other data while waiting for say an OK after an AT… As an example!

Any ideas or suggestions are welcomed!