Thank you for sharing the detailed information and troubleshooting steps performed.
In the screenshot shared above, the preflight dialog looks completely blank. We suppose,
1- It could be a document-specific issue. Where this document's security doesn't allow to show the content details. For testing, check with other file.
2- Disable the security setting and then try running the preflight tool
Navigate to Acrobat>Edit>Preferences>Security (Enhanced)>disable "Protected View" and "Enhanced Security">OK>close and reopen Acrobat.
3- If nothing works, then once again,
Run this cleaner tool to remove the existing installer and application’s files traces:
Download the Acrobat installer from here: