I'm currently using Windows 11 latest build (22000.65), I am signed up to the Windows Insider Program on Dev Channel.
I wanted to take advantage of the design refresh for Office Insiders. I have a Microsoft 365 subscription, and I joined the Insider program by signing up for the beta channel. I updated the program to version 2108 (build 14301.20004).
Unfortunately, this has changed absolutely nothing for Office. I don't have access to the new interface, no megaphone at the top of the window.
I reinstalled it in offline mode and updated it again, nothing helps.