Software downloaded from sources other than the official App Store or Apple's website may contain malware. These malicious programs can compromise your data, damage your system, or even turn your computer into a botnet client.
Even if you successfully download and install macOS Big Sur from a repackaged ISO, there could be compatibility issues, especially if you're installing it on non-Apple hardware. Apple's operating systems are optimized for their own hardware, and performance or functionality issues can arise. macos big sur 1101 20b29iso google drive repack