The key is to (1) make this arrangement explicit and regularly check in, and (2) find non-promotion ways of rewarding and recognizing good work. This will be dependent on the person, and isn't as clear cut as the promotions track.
I think it's great to just be happy with what you're doing, and focus on other things in life.
[1] https://www.goodreads.com/book/show/29939161-radical-candor