Restore of my iphone7 backup to my new iPhone SE.

Hi, I recently got the new iPhone SE and restored the backup from my old iPhone 7 to the new phone. I am shocked to see how the iPhone had not backed up photographs and some what's app media which had been downloaded to the phone and did not say anything over all these months about the backup not happening properly. Fortunately I backed up my photos to Google Photos which seems to have done a better job than iCloud. True I did run out of storage at one point and I could see messages on my phone saying it could not be backed up. But once we upped the family storage I would have thought that iCloud backups would be reliable. Not so. So what is the best way to restore my photos from google to my iPhone and WhatsApp media seems not to have been backed up. Does anybody have ideas on how to restore downloaded whatsapp media messages from my old iPhone backup. I have reset my phone twice already and each time the whatsApp did not load fully forcing an updated and not reading my media. Does anybody know how I can restore my iPhone to and Android?

Thank you,

Shanthi260