1st gen 128GB iPhone SE has 3.9TB estimated backup size + more issues
I'm at my wits end. I've tried every possible way you can think of to backup this phone. Different networks, reducing the backup size, I've been to the Apple store TWICE. They tried to connect it to Etherent and no adapter in the store would work with my phone. I've been told my SE is probably old enough that it doesn't have the hardware compatibility to use the adapters. I've also tried to transfer directly to my new phone, a 512GB iPhone 13 mini, the transfer will either force quit after hours of saying "preparing to transfer" or it will tell me the Mini doesn't have enough storage to complete the transfer.
I don't know how a 3.9TB size backup is even possible from a 128GB phone.
I've had this phone for 6 years, most of my things I can sync in the cloud and bring it down to a new phone setup but I have locked notes I can't get into that are local to the device. The SE won't upgrade far enough to let me change the password without knowing the old one, so the only way I can get into those again is with a direct transfer to the 13Mini.
I've been trying different solutions for months now, but nothing I've found online has worked, and both times I visited the Apple store I left them as confused as I was when I got there. I'm not asking for the obvious "just start over on the new phone with the synced data," I'm looking for a relevant piece of advice. Please keep that in mind.
Attached images of the estimated backup size and my iCloud storage. Phone storage is 70GB taken up out of 128GB
iPhone SE