Growth mindset does not imply you can achieve anything, just "you definitely can get better". Perhaps overconfidence can become a risk, but it seems a much lesser evil versus the cost of believing the opposite: "Here is your definitive level, for ever (don't bother)".

> Perhaps overconfidence can become a risk, but it seems a much lesser evil versus the cost of believing the opposite: "Here is your definitive level, for ever (don't bother)".

I think it depends on the individual (situation) which mindset causes higher costs.