I have solved my MacBook by switching to use the NEW outlook in 16.57. I had tried everything else, without success. My problems started in Mojave where not all searches would work, I only saw half the items that should have been found in mail and contacts. I did the following several times. re-index, using various methods. new profile delete and reload accounts upgrade from Mojave to Monterey. Tried it all again. Mine would work while indexing, then all disappear. if I searched using spotlight it worked, but not if I used search in outlook. As soon as I switched to NEW outlook, bingo. all searches now work. I had previously tried NEW outlook, but switched back as I am a bit of a dinosaur!! Hope this works for others.