There is a bug in restoring Intel Macs because MacOS Big Sur cannot be downloaded. The restore feature is supposed to restore that version, but it is actually macOS Catalina that is being downloaded.
According to MrMacintosh, this bug has existed between Intel Mac downloads and macOS Big Sur since early December. Apple would know, but there is no information on the date of a fix. It is possible that the situation will resolve in January when everyone is back to work. But that has yet to be confirmed.
The macOS recovery function will run as soon as the Mac is turned on. You’ll need to hold down Command + R when the Mac beeps on startup. A menu appears and allows, among other things, the reinstallation of macOS. During this process, a request is made to download the operating system to Apple’s servers. In this case, the Intel Macs will download macOS Catalina even if the computer is running macOS Big Sur.
It is good to note that this macOS Big Sur bug only affects Intel Macs. However, it is possible to reinstall macOS Catalina and then switch to macOS Big Sur. Apple Silicon Macs with the M1 chip have the right to another process and are not affected by the error described here.