This looks like a Microsoft issue with the old user interface. If you switch to the "New Outlook", the search is working for me. Maybe this is Microsofts way of pushing the new UI :-D

Similar problem here. Since Big Sur my USB-C ports randomly stop working in respect to charging. The battery runs empty although the Macbook is connected to the charger. If I change the port it suddenly charges again. This is particularly annoying when leaving the Macbook closed lid and coming back after some time finding the Macbook battery completely drained.