RE: I GIVE UP !!
You said you have been practicing with your trainer? Is it still fly-able?
Go out and fly that one. If you enjoy doing that, then stick with the hobby. Look at the Sundowner as a goal. "Someday, I'm going to be flying the wings off it. Just wait 'n see."
Many people on this forum will attest to retaining their trainer just so they can go out and have a relaxing, fun, fly. They don't have to be "on the sticks" every moment of flight time, as you would need to be with the Sundowner.
So, keep your trainer. Whenever you get frustrated with your other bird(s) or manuals, or radio, or whatever you're trying to learn. Step back, and take your trainer back out and fly it.
If you find this too much, then yes, walk away from the hobby. It'll be sad to see you go. But not all hobbies are for everybody.
Good Luck,