API sync is not working on mid-size ecommerce

I spent hours trying to debug the sync issues that I’ve experienced with this plug-in.
Mailchimp’s assistance has been totally useless, asking me to do tons of stupid tests, and finally… nothing solved.
I’ve a mid-size database (less than 2000 orders) that can’t be synced with Mailchimp due to API’s overload. Once sync is lost, the only option is to restart sync from scratch: disable sync, totally remove the plugin, reinstall, reconfigure and restart sync.
The worse thing is that, as consequence, automations didn’t fire, and they must be recreated at any new sync. That means everyday.

Do not use this plug-in.