Security & Privacy won't open - System Preferences Freezing

Try deleting the plist file for System Preferences.

In Finder, press Command-Shift-G and paste

~/Library/Preferences/com.apple.systempreferences.plist

drag the file out of the folder, for example, to your Desktop, and restart.

If the problem is solved, you can drag the old plist file to the trash.

Yet another test: make a new admin user, logout from your normal account, login to this new admin, try System Preferences->Security & Privacy.

Does it work in this account? Does it work in this account, at least in Safe Mode, if not normally?

If yes, then there is something weird in your account.

If not, then it's probably time to do a clean install of the OS.

This could also be attributed to using some Third Party Disk Cleaner or Disk Optimizer applications that have mucked up the Admin Account of this computer.

Predicated on that being a possibly, the earlier suggestion to Wiping the Drive and reinstalling from zero maybe required.

If going that route - it would be recommended Not to Migrate things back from the TM Backup.

That would just reintroduce the already existing issues that were present when the last TM Backup was created