Hi Kwin,
I do not know of a way to easily check and ‘fix’ that for many Objects at once.
There might be an Addon for it, but I don’t know that either.
The only way, I can think of, is to Select all Mesh Objects (use the Selection Filter), CTRL+J. Go into Edit Mode. A to Select everything and then M > Merge > By Distance. Then P > Separate > By Loose Parts. The huge disadvantage of this method is, that your Object Names are ruined. As well as any Collection structure.
