There are managers who know everything, and they are undoubtedly very hard to deal with.
Managers who know everything may hire you because “they do not have time”, or need more data, or in order to carry out change under the artillery coverage of an OD project.
The first task is to try and understand the reason for your service being commissioned.
I will share 3 things I have found somewhat useful in dealing with managers who know everything.
1) Try and focus on the future. No one really knows all that much about the future. Even the omnipotent know-it-all may show some humility when the discussion is future focused.
2) On certain limited issues, stand your ground and label differences as “disagreements”. You will get push back, which is the time to then focus on the issue: “do I need to agree with you on everything”, here and now.
3) Where possible, don’t get involved trying to prevent a fire; wait till things get really bad. Even managers who know it all are more flexible when massive dysfunction heads their way.