If you still want to stay with park flyers or electric.

Invest in a 4-6 channel radio system...opt for the micro servo options of course.
Invest in a good motor control and motor.

maybe try the GP ugly sticks or similar models.

Models come and go.
You can make repairs , purchase, or scrath build models.

bascailly use the electronic/motor on different models.

Smaller models are actually harder to fly becuase of the wing load. You have to keep up the air speed.

When I taugh my son how to fly. I bascailly used a duraplane. (nitro).
It survived the many and many mistakes he had to endure. Mostly on landing procedures or approches.lol
Plus it releaved the pressure of him crashing... i didn't get mad at him if he crashed. It made it more enjoyable for him.
He wasn't really into r/c or aviation, but it was something I could pass on to him and time i can spend with my teenage kid.
Obviousely...he wasn't going to go out of his way and reserch on flight theory...