Apple calendar invites don’t reach invitees - why?

Operating on iPhone 13 Pro, iOS 15.1.1.

Apple calendar events don’t reach invitees at all, however read as “no response” when I invite them. I’ve tried sending these calendar events to various attendees via SMS, email, toggling with certain fields, switching from WiFi to LTE - nothing. It’s like the invites get lost in space.

I see on these Community forums, a good deal of folks have been trying to raise this to Apple support since 2017, yet no real action is taken.

Can someone please clarify if Apple is working on this, or if they’re ignoring it for some reason? I find it bizarre that such a simple bug - a calendar invitation! - would go ignored for years, but it sounds like Apple has no interest in functional calendar invites at the moment.