Hello KLLasks,
Welcome to Apple Support Communities. We understand the importance of having your calendars, and photos syncing between your iPhone and iPad, and we'd be happy to look into this with you.
Just to clarify, if you added an event1 for example to your calendar on your iPhone, it won't show up on your iPad? What if you added event2 for example on your iPad, does it show up on your iPhone?
If you go to iCloud website using a web browser on your computer, and checked your calendars, do you see event1, and event2?
Let's repeat the same steps regarding photos to see what happens.
To get started, please check out these helpful links:
Keep your Calendar up to date with iCloud
If your iCloud Contacts, Calendars, or Reminders won’t sync
Keep your photos safely stored and up to date on all of your devices
Let us know the results, and we'll go from there. Kind regards.