I want to confirm that the Magento 2 Abandoned cart email is not a default feature? MagePlaza extension inside the Magento seems need to get paid for this function.
Thanks
It is
You can enable that feature in Store>Configuration>Engagement Cloud>Abandoned Carts
but the only issue is, it is also a paid service.
reference: https://docs.magento.com/m2/ce/user_guide/configuration/engagement-cloud/abandoned-carts.html