WordPress - Create limited site owner role

functions.php

<?php

add_action('after_setup_theme', function(){
	if(!get_option('soes_roles_created')){
		$site_owner_caps = get_role('administrator')->capabilities;
	
		$unwanted_caps = array(
			'activate_plugins' => true,
			'delete_plugins' => true,
			'install_plugins' => true,
			'update_plugins' => true,
		);
		
		$site_owner_caps = array_diff_key($site_owner_caps, $unwanted_caps);
		
		add_role('site_owner', 'Site Owner', $site_owner_caps);
		
		update_option('soes_roles_created', true);
	}
});