icloud photos

hello!

i have recently transferred over to a new iphone and wanted to transfer my icloud photos as well. however, the transfer had first been stuck at 1% for this to now have appeared and soon after disappeared as well.

the photos from my old phone have still not transferred, despite both phones having the same software version (13.5.1)

should i perhaps update the software on both phones for my photos to transfer?

please help me with this. thank you!