The research around it is true, in that believing you can get better at something helps you get better at it more than if you think you are “genetically predisposed” to a certain level of performance in said task.

I think your experience of it being infantilizing is more due to the general cheesiness of psych and health learned in school when you’re young. When you’re young, you’re told all these ideas about eating healthy, sleeping early, adopting healthy psych techniques to help you succeed, like the growth mindset. At the time, we often disregard them as just irrelevant things that adults tell us, only to find out when we’re older that everything they said was right and they just kind of sucked at explaining it.

I myself am going through this revelation of eating healthier, sleeping better, learning useful techniques in therapy that all were touched on in grade school, but I didn’t take seriously back then until I ran into the problems I feel now.