There's a difference between being a high achiever, and being able to rightly and fairly recognise one's own (and others') achievements...
'High achiever'
can be an excuse for never letting yaself be good enough. Always needing to do better.
Which can be quite a sad place to be, IMO. And IME. Driven but... Going nowhere. Because IME for a long time the best I could do was what I *should* be doing. So wasn't owt to be proud of / wasn't anything special.
"Better a pig (called Trevor) and happy, than Socrates and unhappy" innit
Someone who's happy with a 2:2 / third is - IMO - better off than someone who's got a first but isn't proud of it / happy with it.