So, I don't know about the OP, but we know how to check on the address and set forwards and such. The problem is that the emails AREN'T being passed through by apple systems. I have the same problem, any website that I use hide my email on, if I need to do a password reset, or anything like that the emails never arrive. It seems to me like apples systems is filtering them out either thinking their spam or erroneously thinking they're protecting us.
Why am I wanting to reset the password of a hide my email? Because the apps website is not set up to use Apple Login, only their app. Which means we can't get into the website anywhere except the app. This is not always ideal if the app is not presenting a certain functionality or requires using the website for certain reasons.
In my most recent example (last 48 hours), Hide My email won't even forward the "confirm your email" request that the app is doing.