Install cocoapods with gem not with Homebrew
sudo gem install cocoapods
but first find stable version of gem and ruby

if already installed then update gem

gem update --system
Install Ruby via RVM
1. Install RVM as per instructions

or

curl -L https://get.rvm.io | bash -s -- --version latest
then

source ~/.rvm/scripts/rvm
type rvm | head -n 1
If the output is:

rvm is a function
You may need to add "source ~/.rvm/scripts/rvm" to your ~/.bash_profile file

2. Install Ruby

rvm install (ruby version)
rvm --default use (ruby version)
eg:

rvm install 2.7.2
can use rvm list to see available ruby versions.

check location of ruby

which -a ruby
which ruby