[SharePoint Online] I have a large document library that uses document sets extensively. We just changed it from classic view to modern view, to see if users liked that. The problem we're running into is that search functions differently. Primarily, if they search for an ID number, it still brings up all of the documents from within a document set and the document set with that ID, but the document set cannot be opened from search results. No amount of clicking on anything will open the document set or get a menu that allows us to open it. Basically you can find the document set but not do anything with it. So it's not a search issue, it's an interface issue.
This is a massive library (20,000+ documents), so I cannot make changes to it easily.
Edit: The issue seems to be isolated to this one library. Other libraries in this site do allow opening the document set from search results. I can't figure out what setting it might be that is causing this behavior, or if it's related to the size of the library, or something else I haven't thought of.