Not sure if it's too late, I have similar issue. It's because the installed aws executable is not in executables path, you can do either of:

Option#1: create sym link

sudo ln -s /Users/fr/.local/lib/aws/bin/aws /usr/local/bin/aws

Option#2: Add path to zshrc file

echo 'export PATH=/Users/fr/.local/lib/aws/bin/:$PATH' >> ~/.zshrc

source ~/.zshrc