Hello,
I'm sorry but that's not possible: this would mean to trigger a backup using a system plugin (while the regular page loads). We used to have a plugin like that, called "Lazy backup schedule", but it turned out to be very unreliable so we killed it.
In your case the best option is to automatically take a backup every month, that should cover you in most of the cases.
Davide Tampellini
Developer and Support Staff
🇮🇹Italian: native 🇬🇧English: good • 🕐 My time zone is Europe / Rome (UTC +1)
Please keep in mind my timezone and cultural differences when reading my replies. Thank you!