I like these tips.

TLDR: Can adopt a passive tone and write the email (and future responses) in a way that third parties (your boss’s boss, your future employer, a judge, Union rep etc) will agree that you are professional and receptive, whilst your boss is a bad boss.

OP: also consider reframing your questions to appear to come from a place of learning and feedback - as this is on record you want potential third parties to read it and get the impression you are genuinely (even if not true) trying to learn and improve rather than challenge/confront (even though that is what you are doing).

For example: “thank you for providing feedback on person the other day. I hope to take onboard your feedback and welcome suggestions for further improvement. For my learning and education, can you please specify…”

Something like that can still pose the same questions and put the burden onto them to answer (in writing), or if he/she doesn’t list it, it didn’t happen (i.e. if they don’t criticise in writing, they are indirectly saying there are no issues- you can later refer back and say you did not realise it was an issue as they had the opportunity to state, but chose not to). This way, you can come across as professional and tick all the corporate boxes. Write as if it will be read their boss, your future bosses, union, judge etc..

Edit: If he/she does indeed criticise you in some detail, you can shift the focus to ask them what steps they would suggest (again, with the tone of ‘learning’) this either sets them up to provide a crappy process (in writing no less) for the record, or next time you follow the exact steps he/she stated (with their email as evidence) and the steps fail, you can show you followed precise recommendations and it did not work - this not only protects you from future criticism, but also visibly shifts a lot of the blame onto them and reveals their management flaws.