It's common advice to "not look for external validation", but in a lot of cases this advice isn't really heplful, because the reader's problem isn't that they don't know that's their problem, but that they don't know how to not depend on external validation.
Emotions aren't things we control at will. We can't just choose to not be upset by something.
Sometimes people say "don't compare yourself to others", but that's borderline troll advice. Not only is comparing oneself to others about as intrinsic and inevitable as needing company, but it's a very useful practice. It's valuable to know what the standards for measurement are, and comparison to others is how you see that.
I'm going to try to say something a little more concrete. If anyone who struggles with this is reading this, they can tell me whether my advice was any more helpful.
There are two ways to not depend on external validation: get internal validation or get used to not having any.
The first way only works if there's something valid to admire about yourself. For some people, there is and they just haven't noticed it.
But if you can't validate yourself, there's another path: you can accept that there's nothing to like about you. If you normalize seeing yourself as a failure or a bad person, you protect yourself from other people telling you that.
This second way does work; it's what I've done. If you're not an admirable person, trying to get internal or external validation is worse than hopeless, because you can end up getting validation from something you shouldn't.