Replacing my ipad pro 9.7 128gb with ipad pro 10.5 256gb, backup?

[Oyeve]

I am swapping my ipad pro 9.7 with a new ipad pro 10.5. The 9.7 is 128gb and is nearly filled up with movies I copied via "sendanywhere" app. I backup up the 9.7 via itunes but the back up was only 11gb. Is there a better way to take a full back up? I just want to swap all to the new ipad. I hate itunes.