Hello twocoaststoo,
Ensuring your notes are loading as expected in the Notes app is important, and Apple Support Communities is a fantastic place for help! From the description you provided it sounds as though the notes are appearing when opening the Notes app, but when opening the specific note the content isn’t loading. You mentioned that the notes are synced to iCloud. If you sign in to the iCloud website does everything appear correctly?
If so, and with having already restarted your device. The next step would be to confirm you’re running the latest iOS. You can find the steps for updating in the following article.
Update your iPhone, iPad, or iPod touch
You may also want to make sure you have enough available storage on your device. You can verify the storage usage in Settings > General > iPhone Storage. If you need to make more available space, the following article outlines great tips on how to manage your device storage.
How to check the storage on your iPhone, iPad, and iPod touch
Have a wonderful week!