Homebrew: Your CLT does not support macOS 11.0
Simplest solution that worked when upgrading to Big Sur. A clean install may not require the solution below. There is inconsistency with the way CLT is upgraded to 12.2.
sudo rm -rf /Library/Developer/CommandLineTools
sudo xcode-select --install

Worked with the following versions (post-install)
❯ /usr/bin/xcodebuild -version
Xcode 12.2
Build version 12B45b

❯ pkgutil --pkg-info=com.apple.pkg.CLTools_Executables
package-id: com.apple.pkg.CLTools_Executables
version: 12.2.0.0.1.1603499215
volume: /
location: /
install-time: 1605632122
groups: com.apple.FindSystemFiles.pkg-group

Big Sur
11.0.1 (20B29)