So, this happened with my boyfriend's phone (16 pro). through trial and error I figured out that I had to wipe the phone, do a fresh install of 26.0.1 and then restore individual things from icloud. If you log into your icloud account you can restore your contacts and calendar. if you had your photos saved to icloud, they will be available when you log into your apple account from your phone. messages will also be restored. (we noticed not all of the messages are restored, but most are.) if you go to the app store, you can click on your profile, go to apps > my apps, you'll see a list of all the apps you've had on your phone and re-download them. The 'Passwords' data will also download automatically, but you have to open the app first.
I tried restoring from a few save points and all of them would throw the phone back into recovery mode and loop. I had to use a program called AnyFix to get it out of the recovery loop. It seems like something with this update corrupts the backups. I havent been able to narrow down what the failure point actually is. Finder did not work (I have a PC not a mac)
I know this isnt the best answer, but at least you can get some of your data back.