How to set a new iPhone Backup Password for new backups

Unfortunately, I have lost/forgotten the password for my old iPhone backups. I understand that I cannot access any old backups without having the password to those backups, but I want to be able to create usable backups going forward. It seems as if that password is burned into the phone forever and that I cannot create a *useable* backup now or in the future without having the old password. The only useful suggestion I have found is to Reset the phone, not clearing data, which some posts suggest will lose the keychain and Wifi passwords. So if that's the only way, is there a way to separately backup the keychain and Wifi passwords? Obviously I can't rely on the normal backup system.