How can I delete cloud saves of a game or disable cloud saves altogether?

You can't disable cloud saving while online. What you can do is delete the local and cloud saves of a title associated with your account and play the game offline.

When managing a game, if I go into the "game & add ons", there is a button that says "delete all". If I go to a save folder (provided it exists) and select that option, it deletes... but as soon as the game is restarted, it goes right back to "syncing from cloud", and the save games are loaded right back in, even if days pass before starting up again, so there is no issue with "enough time for the server to update" Other games only show "reserved space" as a save... and no "delete everywhere" option exists.

...and that still doesn't answer the root issue: no option exists to modify or disable 'cloud storage' altogether to keep all saves local on the console.

Have you tried disabling Cloud Saved Games? Highlight the Cloud Saved Games storage device, hit Y, then Disable.

If cloud saves were deleted, im not sure theres anything to recover. Cant imagine if this would work, but deleting and reinstalling the game might reset the account back to a cloud save but since everything cloud saved is constantly updated...might be
stuck at the moment. How was the cloud data deleted?

If I disable cloud storage, won't it delete all of the saved games that are in currently saved there?

I have tried going to the option and taking the option to enable cloud storage, just in case that was the problem. But doing that did not resolve the issue.