When you Reset Protected Data, the only thing you will lose is Keychain, Home (smart devices, home security, etc.) and possibly some other passwords on your phone. But mostly just keychain. I was on with Apple Support, and they said just keychain, though the prompt said Keychain, Home, and something else I can't remember at the moment, but all I saw when I did it was "Resetting Keychain........" and that was that. No big deal since I don't use keychain anymore anyways. I haven't in a long time. Never ended up using it even after I added my cc info in the first place several years back. So go ahead and click Reset Protected Data. That is the recommendation from both me and the AppleCare Senior Analyst Support tech that I was transferred to after talking to a regular Apple Support person in Apple Support chat.
The AppleCare Support Tech said you will not lose any iCloud data except keychain. None of your notes, pictures, contacts, or any other data will be lost.