Using New Outlook on Windows for personal email, calendar, and contact management
I also have this issue and repairs don't resolve it. There is no option to send to the whole group or added/removed attendees. I'm also using Outlook Windows desktop app, and I'm on Windows 11. I have confirmed with our internal IT that they have not done any custom configuration to it.
As an aside, I don't know where to submit general feedback about the new Outlook, but for as slick as it looks, you got rid of so many features that my colleagues and I have counted on for years (advanced rules, advanced quick steps, more options in search folders, etc.). This is going to greatly increase how much time I spend managing email/events because of these poorly thought out changes. Maybe you should have made Outlook for the Web more like the WIndows version instead of vice versa.