iCloud replaced all my pictures on camera roll with my old phone

I have two iPhones that share the same iCloud and never had any issues with my camera roll.

However, yesterday morning I found that my camera roll from my old iPhone has completely replaced the camera roll on my new phone - All pictures that I have taken on my new iPhone has been completely wiped and replaced with the pictures on my old iPhone.

Is there anyway to recover my pictures on the new phone?

I've tried everything, there's no files to restore on iCloud and there's no Recently deleted pictures either. I restored from a previous backup and it does not contain my pictures, nor, does restoring from iCloud backup works.

Please help.