Regarding over the top accomplishments in resumes: every resume writing workshop tells you to do this. I don't think you should be rejecting these first just because someone listened to the advice of "sell yourself".
A lot of people think they're way better at hiring than they are. Just like employees overestimate their skills (and are encouraged to because the resume process) employers also over estimate their hiring skills (and are encouraged to because the bureaucratic process).
Judging from the results for people I know who've had this person re-work their résumés, it's extremely good advice. Non-braggy résumés seem to just get round-filed for not knowing how to play the game, even if they're otherwise very well-written. I'm sure there are a few folks hiring—probably almost all at relatively small enterprises—who have the opposite reaction but they're instead rejecting good people who are simply playing their hand the best possible way, given the rules. Those who fluff up their résumés get much better results.
That doesn’t make sense, there must be a different causality.
To be clear, per parent, I'm not saying to lie but things can generally be presented in a positive way.
The squeaky wheel gets the grease.
People can have fewer accomplishments and make a big deal out of them and get more out of it. I would rather not make a big deal out of meaningless stuff. I recently certified as an AWS practicioner after my associate level certs expired. My manager wants to send an email out to the department about that accomplishment. I don't get it - it's just practicioner.
For example, if you say that you "developed software that saved the company $X million/year," that might look good to a non-tech person but a tech person will understand that could mean nothing. Maybe you spellchecked comments in a sub-subcomponent of a project a thousand people worked on. On the other hand you might say you "worked on v1 of the Frobnicator library" which might look like nothing to a recruiter but which is a legendary accomplishment in the field.
In my case I just say what I did in plain language that includes a bunch of keywords and hope that's enough.
I've been in the bracket where ageism is a factor for a while now and so have many of the best people I know who still work as ICs. Being told that no-one really has that breadth or depth of experience and unicorns don't exist should be surprising for this group but sadly isn't any more. If the person making the silly comment is an important player in a hiring process then that's not a good sign.
The worst I've seen is when you're personally invited in as an expert/consultant by someone in your network and then HR insist on treating the gig as if they're hiring some random junior developer applicant. Objectively the professional thing to do if you're getting messed around like that is usually to politely disengage but then you risk making your friend/colleague look bad. Sometimes going via your network is a double-edged sword.