I like the idea of running this through a schedule event in WordPress, https://codex.wordpress.org/Function_Reference/wp_schedule_event
Here is a snippet that hopefully will get you there:
<?php
if(!wp_next_scheduled('daily_plugin_check')){
wp_schedule_event( time(), 'daily', 'daily_plugin_check' );
}
add_action( 'daily_plugin_check', 'toggle_plugins' );
function toggle_plugins() {
switch(date('D')){
case 'Mon' :
case 'Wed' :
case 'Fri' :
// Could be an array or a single string
$plugin_to_activate="akismet/akismet.php";
$plugin_to_deactivate="akismet/akismet.php";
break;
// Continue with each day you'd like to activate / deactive them
}
if(!function_exists('activate_plugin')){
require_once ABSPATH . 'wp-admin/includes/plugin.php';
}
if(!empty($plugin_to_activate){
// If $plugin_to_activate is an array, then you can foreach of it
if(!is_plugin_active($plugin_to_activate)){
activate_plugin($plugin_to_activate);
}
}
if(!empty($plugin_to_deactivate){
// If $plugin_to_activate is an array, then you can foreach of it
if(is_plugin_active($plugin_to_deactivate)){
deactivate_plugins($plugin_to_deactivate);
}
}
}
Hope that helps!