To avoid exception messages from crashed BackgroundService instances in the .NET console output (STDOUT), you can handle exceptions more gracefully by using one or more of the following techniques:

1**.Override ExecuteAsync in the BackgroundService:**

Override ExecuteAsync and wrap your background task in a try-catch block. This lets you catch exceptions without them bubbling up to STDOUT.

2.Set IHostLifetime to Null:

If the exception is unhandled and crashes the application, the default behavior of IHostLifetime (like ConsoleLifetime in a console app) can propagate the exception to STDOUT.

3.Suppress Unobserved Task Exceptions:

Sometimes, background services crash due to unobserved task exceptions.

4.Graceful Shutdown with Try-Catch:

Add try-catch around the shutdown code.

5.Logging and Custom Logger Configurations:

Consider logging exceptions using a logger instead of writing to STDOUT. Configure logging providers to direct messages to files or databases rather than the console.