When I got into RC and before I came across FT, I was also looking at gyro receivers. Like you, I bought an AR636. There was a huge learning curve for me, as at the time I was not a very experienced pilot. The biggest hurdle for me was learning how to program the AR636 unit. You need a laptop or a cell phone, and then you also need the appropriate proprietary Spektrum programming cable. If memory serves the cable alone was $20, and without it you are unable to turn on the gyro functions of the RX.
Once I got over the initial hurdles and finally got my AR636 dialed in, it proved to be a decent unit. It is somewhat obnoxious to program and adjust, as every time you want to adjust gain settings, you need to plug in the programming cable and phone/laptop again. It is cumbersome and I found it tiresome after a while. It is also worth mentioning that no matter what you do, an off-the-shelf AR636 will never be able to have "SAFE" functionality where it limits bank and pitch angles and gives you a panic recovery switch. Only PnP or BnF models from Horizon will have that feature. I still have my AR636, but I have since restored it to factory defaults and just use it as a "dumb" RX.
Do not despair, however, as there is a better way. LemonRX makes a few different stabilized receivers that have basically the same functions as the AR636. The best part? The Lemon units only cost about $25-$35, and all adjustments can be made on the actual unit itself with a small screwdriver. It can handle V-tails, elevon mixing, and individual adjustment of rudder, elevator, and aileron gain settings. They don't have SAFE either, but neither does a loose AR636. I have since bought 4 of the LemonRX units and can't say enough good things about them.
One last thing I should mention: To really get the most out of the LemonRXes, you need to have a computerized radio like a DX8e or similiar. One with a spare 3 position switch and preferably an adjustment knob. The 3 position switch will allow you to turn the gyro feature on and off while in flight (Off/Gyro/Autolevel if you choose a LemonRX Stabilizer Plus). The knob will allow you to adjust gains while in flight, which is just an awesome feature. It cuts tuning time down to a fraction of what it used to be as you can get a plane dialed in in a single flight vs. several flights to adjust settings.
I'm happy to answer any other questions you may have, feel free to shoot me a PM or we can continue the discussion here publicly.
Stabilizer PLUS:
https://www.amazon.com/dp/B01N188KKR/?tag=lstir-20
Stabilizer only, no autolevel feature:
https://www.amazon.com/dp/B01MXFB4UI/?tag=lstir-20