Update / proper solution:
https://www.prodjex.com/2017/07/composer-issue-on-linux-with...
Trial and error below:
Go into the home directory of the user
Edit .bashrc and add the php version you want to use (php-cli version in this case) as an alias for php
For example in my case, php-cli for php v7 was located at /opt/cpanel/ea-php70/root/usr/bin/php
And to my bashrc file I added
alias php=/opt/cpanel/ea-php70/root/usr/bin/php
And that finally got the composer and other php cli commands working.
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