brew install latonz/dotnet-sdks/dotnet-sdk-<version or channel>
Or brew tap latonz/dotnet-sdks and then brew install dotnet-sdk-<version or channel>.
<version or channel> can be any dotnet sdk version or channel with all dots replaced with hyphens (ex. 6-0).
Example: brew install latonz/dotnet-sdks/dotnet-sdk-6-0
brew uninstall --zap --cask dotnet-sdk-<version or channel>
brew help, man brew or check Homebrew's documentation.