“Under qualified for your years” is ageist bullshit. You’re either a capable L3,4,5,etc. Any coupling of those achievement brackets to age ranges (which cannot be completely detached from experience level) is discrimination.
True. As if they expect every 80 year olds to be nobel laureates. The thing is those with power to hire are hardly smart people, they just happen to have the power to hire, by chance.
However the fact that you are using numbered levels instead of broader decscriptors like "junior" and "senior" means that we are thinking on different wavelengths. I guess you're talking Google-ese because it is harder to know what is "L3" without context.
I have obtained various kinds of feedback and working on some of my weaknesses, but "underqualified" and "repeating the same basic experience many times" are the most common themes.