Hi @Aleem Sheikh ,
Did you search for the issue for the first time after completing the migration, or did you reproduce the issue multiple times? Or is the issue after you tried to search after these next steps?
Generally speaking, the search function takes some time to crawl and return the results. If it no longer appears "Your search returned no results" after being able to search correctly and work stably and correctly, then it is normal.
Reference:
Search in SharePoint
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