Thruster Speed Control




I have a question that might seem to be sort of basic -as I am still a newbie in this area- I am trying to find a way to obtain thrusters rpm, some experts suggested to use a BLHeli32 ESC can help me with such thing for speeds above 1000 rpm, after searching the internet for a while i found i can get from those ESCs the RPM readings for each thruster separately but i only found in telemetry mode using betaflight for (quadcopters, aerial drones…)

My first question:
Is it possible that i can obtain the thrusters speed while i am in the operation not only during the betaflight configuration operation?

My second question:
Do i need a FC to get the RPM readings from the ESCs or it can be used with my main controller (Ex: RPI) to be used in my PID Loop?

My third question:
What other options do i have if i want to get the RPM of my thruster to be used later in my control loop?

Note: I am not interested in showing the speeds on a screen or such a thing just need the readings for the control loop

Thanks in advance.