I found a problem and the solution, if someone here is with the same problem:
macOS Big Sur does not find new updates: To use the 'Kext-Droplet' Software, it is necessary to disable 'SIP' using the 'csrutil disable' command in the 'Terminal' of 'Recovery Mode'. However, the 'SIP' deactivation procedure creates a problem in which 'mac OS Big Sur' cannot find the updates available for the operating system (The problem is not fixed even after reactivating 'SIP'), thus making it possible to update only through the Apple Store, requiring the download of the complete system. The solution found was 'Reset NVRAM', however the new Kexts that were installed will be lost. In order to avoid the problem with the system updates, you must install Kexts manually in the 'EFI', without disabling the 'SIP'.