When it comes to interfacing with flight controllers, I would suggest that your best option is Sbus (which is a serial bus interface) its used by: Futaba, FRsky, Radiomaster, Jumper, Orange and other Open Tx source radio gear like Radioking etc. Flysky use there own system called Ibus, its the same principle as Sbus, a single serial lead for data transfer.
If you plan to use a Spektrum system, I suspect your restricted to PWM connections rather than a single serial interface. Unless you opt for a second party DSMx protocol receiver with an Sbus output, like the Orange one I mentioned in an earlier thread.
You will note I stated that "Sbus is "my suggested" best option. This is because it provides reduced latency over PWM connections and is fairly straight forward to set-up using one lead connection between receiver and flight controller.
However, it would mean changing your transmitter to a system/protocol that supports Sbus as per the options I suggested above.
I may be incorrect regarding the information about Spektrum receivers and apologies if my information is incorrect or misleading. I am sure there is someone on the forum with far more expertise on Spektrum systems and knowledge of their capability than I have. Hopefully they can provide you with better advice regards options with a Spektrum set-up.
If your planning to fly mostly fixed wing planes or helicopters to begin with, it may not be worth investing at this time in a new system, which supports Sbus. Flight controllers and flight stabilisation are not essential, just a nice to have when learning or flying big expensive planes and jets. If you can get away with just using PWM connections, it will be a cheaper option.
However, if you are looking to experiment with drones and multi rotor aircraft in the long term, you will be interfacing with flight controllers in nearly every instances, so Sbus would be the logical way to go.
Hope this helps.