Currently a hybrid blazor app is hosted by the browser sandbox similar to WASM. This limits the what code can be executed. The only supported database is sqllite or the browser’s builtin database via jsinterop.
because the hosting Maui app has access to the hosting webview, you can use messaging for blazor code to call Maui code. So you could define a message api for blazor code to call Maui code to perform database access. Though this would only make sense with a Maui windows desktop app. See the weakmessenger class. Google for blazor examples.
so in short you will create a database api with migrations in the Maui code, not blazor. You will then use messaging for the blazor code to call the Maui code.
note: as Maui Blazor hybrid goal is to create mobile applications, not windows desktop, database access is typically local SQLite or calling a webapi.