Is there a way to send an automated email based on a custom databasse collection?

Hello,

I think the closest thing to the desired functionality will be Recurring Jobs and Triggered Emails:
Corvid: Scheduling Recurring Jobs

About Triggered Emails
Corvid Tutorial: Sending a Triggered Email to Contacts
Corvid Tutorial: Sending a Triggered Email to Members

You can try to contact Wix Customer Care as they know best about the Wix Automations.
https://support.wix.com/en/article/contacting-wix-customer-care-for-support