Step 1
Download the plugin here. and install the plugin on a non WPengine/Flywheel hosted site, I suggest a locally hosted website.
Step 2
Login to your WPengine hosted website and go to your users, edit your admin user and at the bottom create a new application password. Copy this password as you will not be able to see it again.
Step 3
head back to your controller site, jump to Settings -> Plugin Update Sender. Here you enter your site URL such as https://mountainairweb.com your username and your application password, you can add multiple websites. click save
Step 4
Click the Check for plugin updates button. It will take a minute and you will get a list of your current version and latest version of the plugins on your site with a quick button to download those plugins. you can then manually update them and click the check plugin updates button again to see if you missed anything.