Why can’t you just use pyenv
like @robin0800 told you two days ago?
$ sudo pacman -S pyenv
$ pyenv install -v 2.7.18
Then run pyenv init
and follow the instructions. After restarting your terminal;
$ python --version
Python 3.11.6
$ pyenv shell 2.7.18
$ python --version
Python 2.7.18