Firebase Cloud Firestore rules: all users can read, authenticated users can create if they provide a UID, owner can delete, owner can update.

firebase-owner-firestore-crud-rules.txt

service cloud.firestore {
  match /databases/{database}/documents {
    match /<COLLECTION_NAME>/{document=**} {
      allow read: if true;
      allow create: if request.auth != null && request.auth.uid == request.resource.data.uid;
      allow update, delete: if request.auth != null && request.auth.uid == resource.data.uid;
    }
  }
}