How not to get more stuck as we get older?
Learning works by a lot of repetition
Thinking patterns can be hard to and take time to acquire
But then also hard to call into question, adapt, get rid off?
Same for movements
You know if you've ever tried to change technique
I once thought I had made a major change to my serve
On video it looked pretty much the same as before :)
How can we train the brain
to stay flexible in that regard?
To keep acquiring new things?
Make new connections?
How can we first and foremost learn to learn?
To re-assess?
Without driving ourselves crazy?
Without spending too much time and energy on meta-thinking?
For the physical aspect I'd carefully vouch for
Training for flexibility and variety to begin with (e.g. when young)
First learn or at least try the many different ways to hit and kick a ball
Try different sports
And of course
Use both sides of the body :)
And then
Pick and choose from that toolkit