Please don't confued us
Model-driven apps require a Microsoft Dataverse database. -> YES
A flow instance can only access one Microsoft Dataverse database. -> NO
Canvas apps require a Microsoft Dataverse database. -> NO
Explanation:
• Model-driven apps are a type of Power Apps that are built on Microsoft Dataverse, and can only connect to a Dataverse environment. All the data that defines a model-driven app is stored within Dataverse, such as tables, views, forms, charts, dashboards, etc.
• A flow instance is a type of Power Automate that runs in response to a trigger or an action, and performs a series of steps or tasks. A flow instance can access more than one Microsoft Dataverse database, by using different connectors or actions.
• Canvas apps are a type of Power Apps that are built by dragging and dropping various controls, such as buttons, labels, galleries, etc. Canvas apps do not require a Microsoft Dataverse database, as they can connect to various data sources and services, such as SharePoint, Excel, Twitter, etc