Full WAF mode (Plesk NGiNX/Apache)

So I haven’t been able to get NinjaFirewall full WAF mode to work on a pretty run-of-the-mill Plesk hosting account (using NGiNX as proxy before Apache 2.4).

I’ve tried using php.ini or .user.ini, using Apache/fastCGI and Apache/FPM, adding directives to .htaccess… nothing ever made NinjaFirewall run in full WAF mode.

ninjacheck.php never ever even saw NinjaFirewall running at all.

Now I’m a bit out of ideas. Is there a way to know if a hosting setup simply is not compatible at all with Ninjafirewall full WAF?

PHPInfo says ?no value??for the auto_append_file directive – is this the culprit?

Ninjafirewall Plesk

HTTP server	:	Apache
PHP version	:	7.4.20
PHP SAPI	:	CGI-FCGI
		
auto_prepend_file	:	none
NinjaFirewall detection	:	NinjaFirewall is not loaded
		
Loaded INI file	:	/home/httpd/vhosts/system/domain.suf/etc/php.ini
user_ini.filename	:	none
user_ini.cache_ttl	:	300 seconds
User PHP INI	:	.user.ini found -
		
DOCUMENT_ROOT	:	/home/httpd/vhosts/domain.suf/httpdocs

and using php.ini

HTTP server	:	Apache
PHP version	:	7.4.20
PHP SAPI	:	CGI-FCGI
		
auto_prepend_file	:	none
NinjaFirewall detection	:	NinjaFirewall is not loaded
		
Loaded INI file	:	/home/httpd/vhosts/system/domain.suf/etc/php.ini
user_ini.filename	:	none
user_ini.cache_ttl	:	300 seconds
User PHP INI	:	php.ini found -
		
DOCUMENT_ROOT	:	/home/httpd/vhosts/domain.suf/httpdocs