Hi Guys, My solution (on Big Sur 11.6.2):
Step 1:
Install brew
1. curl -fsSL -o install.sh https://raw.githubusercontent.com/Homebrew/install/HEAD/install.sh
2. /bin/bash install.sh
Step 2:
brew install chruby ruby-install
Step 3:
brew install cocoapods
Step 4: (Check your cocoapods version):
brew upgrade cocoapods
Need Xcode Command Line Tools, if not installed then run this command: sudo xcode-select --install
It's works for me