I bought my 9x less than a year ago and hated it almost from the start - if it works to get OpenTX on it, super, if it bricks it, I still have my Jumper T8SG V2 Pro which is far superior in my view - I've even added the voice option to the Jumper
I agree the Jumper looks like a great system, far better than the 9x. Sounds like you have nothing to lose. I went with Er9x in my Turnegy 9x Pro, it's also got a steep learning curve, not documented all that well. I'm not sure how much different Er9x is from OpenTx.
You need to consider the cost of the Rx. For the most part you stuck with the brand you choose, or at least the protocol. There is a wide difference in the cost of the Rx, some protocols are $8-15 & some are $30-70. I have always gone with the cheap ones, FlySky. I've never had any range issues. Except when I had a crash damaged antenna, but that can happen with any system.
Thank you. However, I've got what I've got and I like it. It's got switches and gimbels and stuff, it feels really nice in my hands, and it's my first transmitter and it is awesome and I could afford to buy it. One day I honestly hope to outgrow it and need something better.
Today, I just want to know if I'm able to set the model to airplane and set my expo's to 30%. Is that enough to fly my plane, or am I missing something?