I am running a multisite network on the latest version of WP. I am the Super Admin.
I setup a user as "Administrator" on a site in the network. The Admin User cannot see the plugins menu.
I completely Network Deactivated all plugins and re-Activated them at the site level.
The Admin User still cannot see the plugins menu.
How can I grant Plugin access to a secondary/alternate Admin?
Have a look at the Network Admin Settings screen (in my installation, it's at example.com/wp-admin/network/settings.php). Tucked away down near the bottom is this:
Menu Settings
Enable administration menus [] Plugins
Checking that box should allow your users to see the Plugins menu in their sites' back end. (I don't think it'll allow them to install new plugins. I haven't tried it out yet, though, so test it before you put it into production.)
Try this - it worked for my situation - add_submenu_page( WP_PLUGIN_DIR . '/multisite-super-admin/includes/admin/settings.php', "Plugins", 'Plugins', 'administrator', '/plugins.php', '') ;
The URL there is to a plugin I wrote. so you will want to add this to your own plugin. Very straight forward.
Learn more about it here - https://codex.wordpress.org/Administration_Menus
