Icloud restore - months of photos missing

I recently had to restore from backup after little sibling disabled my ipad. Unfortunately I only now realized months of photos are randomly missing from my icloud library, during scattered periods over the last two years. It doesn't go up to a certain point and stop, rather, there are obvious gaps here and there where I know for a fact there are photos missing, then the photos continue as normal, a gap again, etc. Nothing is in my recently deleted and I have no options to restore files. What could explain this, and do I have any recourse of finding them again? No local backups unfortunately.

Thank you!