I have created the Rest Api's in .Net 5 and everything was working perfectly but recently I've been moved to .NET 6 and there I've realized that no startup.cs class is present and another thing is how to add the DB Context?
In .NET 6 Microsoft has removed the Startup.cs class.
Now when you'll add a connection string then you've to use builder.Services.AddDbContext
The old way is
services.AddDbContext
Just use
builder.Services
and then you can achieve what you want.