Sudden disappearance of contacts on iPhone despite their presence

I was just browsing on my phone, switching between apps and texting. I went back to text my wife and noticed some contact names and photos from my pinned area were missing. I swapped back to Instagram and texts once more, and almost every contact I have had in my phone for the last decade is gone. There are some random exceptions, but still, people who have their own contact card or I made custom ones for them are all gone.

I contacted Apple, and we went through resetting the network settings, signing out and back into iCloud, turning off contacts, and back on. During all of that, we noticed the contacts were still there. If you go to create a new text message and type the name, it would show as it did, but when I sent the message, it turns into their phone number. So somewhere they're still there. Does anybody have ideas here?

Thank you

[Re-Titled by Moderator]

Original Title: Contacts suddenly disappeared