Additional .ini file

First of all

$ php -i | grep --after-context=5 'Additional .ini'
Additional .ini files parsed => /etc/php/8.1/cli/conf.d/10-opcache.ini,
/etc/php/8.1/cli/conf.d/10-pdo.ini,
/etc/php/8.1/cli/conf.d/15-xml.ini,
/etc/php/8.1/cli/conf.d/20-calendar.ini,
/etc/php/8.1/cli/conf.d/20-ctype.ini,
/etc/php/8.1/cli/conf.d/20-dom.ini,

OK!!!

Now to the /etc/php/8.1/cli/conf.d directory I would like to add a 
personalized file of mine (custom-php.ini).

$ touch /etc/php/8.1/cli/conf.d/custom-php.ini

OK!!!

But I wonder if it is a correct practice, given that /etc is a system 
directory (which contains system configuration files), and the system 
directories should not be touched.
Would it therefore be advisable to specify (through the 
chef_ini_scan_dir) environment variable) an alternative directory?