Issue Can't find PHP-FPM Settings

[ws420]

Wordpress is loading very slow and I want to increase PHP-FPM child
I followed the instructions here and found that the domain is reaching max children

Now i'm trying to follow the instructions here. But i'm stuck at the step where I have to modify PHP-FPM settings. I double-checked here:
Service Plans > Hosting Plans > service_plan_name > PHP Settings
But I can't find PHP-FPM settings on this page..



Same problem for domain's PHP settings

 

[IgorG]

There is notice - For Plesk Onyx 17.5.30 MU#32 and above
Do you have corresponding Plesk version?