I've tried multiple clean installs of 12.2 and 12.3, and every time it throws an error here in Startup.cs

app.UseUmbraco()
    .WithMiddleware(u =>
    {
        u.UseBackOffice();
        u.UseWebsite();
    })
    .WithEndpoints(u =>
    {
        u.UseInstallerEndpoints();
        u.UseBackOfficeEndpoints();
        u.UseWebsiteEndpoints();
    });

The error says:

System.IO.DirectoryNotFoundException: 'C:\REDACTED\myappname\myappname\wwwroot\media'

That folder is in fact missing. So I tried adding the folder manually. Then I get a boot failed error. That tells me to check the logs.

In the logs I see this error:

Configured database is reporting as not being available. ... unable to open database file

UPDATE: I tried to reinstall the template dotnet new install Umbraco.Templates and tried a clean install again. Same results.