Using Classic Outlook on Windows for personal email, calendar, and contact management
I am on Win 11 with the latest version of Office and still have the option to revert. Is the toggle gone from your Outlook screen now?
If you are on a work PC, it may be a global policy your admin controls. If this is a home PC, I saw on a Reddit sub that people without the toggle option have been able to revert by uninstalling the stock Outlook that comes preinstalled on new PCs and doing a fresh download/installation. The new Outlook is still in preview status so there should be a toggle to revert. Then again, we should be able to do all the things we can do in the old Outlook, but here we are...
Hope this helps.