I've used SimpleLogin for awhile and it's worked very well for me, everything shows up and everyone receives their mail as expected, very happy with it. AnonAddy is another alternative, although I personally haven't tested that one. They're both pretty cheap and recommended by PrivacyGuides. SimpleLogin was purchased about a year back by Proton. Who run Proton VPN, ProtonMail and a few other products iirc. https://www.privacyguides.org/en/email/#email-aliasing-services