A plugin to back up subsites in a network

Hello,
I am using wpengine, they are making back ups of my site at least every day. on a multisite I have a total backup which I can restore, this is good but not enough.
I need something that will alllow me to make, at list database backups of each indivudual site which I can revert to if needed.
How can I make this ?
Is there a plugin to such a thing ?
Best regards,
Hervé