Where is the New Outlook Switch?

On both Big Sur and Monterey, Outlook 16.54+, my users' autocomplete/recent contacts dropdown list is incomplete unless they click the search option in New Outlook. Before the removal of the toggle for New Outlook, they were using the classic/"old" Outlook, in which recent contacts/autocomplete worked instantly and with no issues. I did have a couple of instances where it would break and require me to delete the recent contacts database and allow it to recreate, but it would work after I did that (albeit only for some months before needing to repeat the process). I am regretting ever upgrading from Catalina, because my one user in Catalina on 16.56 has no problems with autocomplete on new or old outlook.