How do I retrieve lost emails on my Mail app?

Hello, I have been using the 'hide my email' feature for various services, online shops, newsletters and so on. As I was searching for an older order of a shop where I used the feature, I realised that older emails are no longer in my inbox (on iOS and if I use the webmail service in a browser). The emails which are older than about a year are completely gone and nowhere to find.

It is NOT an issue of filtered messages and only messages which I received through 'hide my email' are affected.

Apple should really warn people that this could happen.

I will stop using the feature and start saving the emails, that are still there.

Any ideas on how to retrieve the lost emails? :-(

[Re-Titled by Moderator]