It looks to me like you might be booting to the live 33 usb then attempting to upgrade that to 34. That will not work since the usb is an iso image and cannot be altered.
If instead you have an installed system on a drive, are booting to that system, and attempting to upgrade that, here is one guide on the steps to follow. This is the official fedora instructions on doing just that.
Many other guides can be found with a simple search for “how to upgrade to fedora 34” or similar.