I understand the long-term damage 'seeking external validation' can do to a person's psyche.

I read something a few days back that you might find useful. Its about a concept called Swadharma from a journal on Integral Health. I'll quote the passage below:

"Title: Swadharma and our psychological Centre

Often the Sanskrit word swadharm is translated as one's duty and this things to mind the notion of external social responsibilities or moral and legal obligations. However that's not how Sri Aurobindo renders it's meaning.

'... to live in one's own self, determining one's self expression from one's own centre of being in accordance with one's own law of being, Swadharma, is the first necessity. Not to be able to do that means disintegration of the life; not to do it sufficiently means lanngour, weakness, in efficiency, the danger of being oppressed by the environing forces and overborne; Not to be able to do it wisely intuitive with a strong use of ones in a material and inner powers, means confusion, disorder, and finally decline and loss of vitality.

Our approach to Swadharma is from this perspective. Swadharm is not an external duty one must perform in society based on any economically or culturely formed roles. Swadharma is one's own law of being, an inside-out movement arising from one's own innermost center. Such a movement is fundamental to the integration, order, and vitality of life, therefore, the wellbeing of the individual and society."

I hope this passage helps you! All the best.