Currently, in the database contents, we can see this limitation:

Databases does not currently support or work with certain Confluence features. Below is a list of some of the critical unsupported features. This list is not exhaustive.
Databases don't currently support:

• backup & restore

• anonymous access

• admin key

• Atlassian Analytics

• Atlassian Data Lake

• data connectors

• screen readers & keyboard navigation

• some Marketplace apps*

• linking Jira from Data Center sites

Please note that most of these features may not be initially supported for databases. However, we plan to add support for many of these features shortly. Please ensure you read the Atlassian Cloud Terms of Service before proceeding. This outlines our terms & conditions.

*Some Marketplace apps might be partially affected when databases are added in a space. See Databases impact on third-party apps to learn more.

Source: https://support.atlassian.com/confluence-cloud/docs/what-confluence-databases-dont-support/

Since anonymous users should see everything on a Confluence site, Database pages should also be visible to them.