serilog-extensions-logging VS Serilog.Exceptions

ILogger is an abstraction provided by Microsoft. It is not a logging framework, it's a way to standardize code to work on any logging framework. In your actual program you need to actually put the logging provider under that abstraction - Microsoft provides some defaults like a console logger, but generally you want to configure Serilog/NLog/whatever. See: https://github.com/serilog/serilog-extensions-logging

Microsoft.Extensions.Logging is a pipeline that uses Microsoft.Extensions.Logging.Abstractions as its structure. It doesn't actually write logs to anywhere or anything, for that you need a provider. Microsoft offers several providers include Console Output, Windows Events, et al. Serilog is just another provider.

You may need to enable logging, otherwise Activity will be null as described here. Regarding your exception message, you're not doing anything with the exceptionHandlerPathFeature object. The documentation you linked to shows some type checking with the is operator to produce an error.

You might also wanna check out Serilog.Exceptions if not already using it. I think that they have some examples of how you could intercept these yourself.

So when we found this out, we rapidly rolled out Serilog.Exceptions that adds this in, and things were better

If you're using Serilog, add in Serilog.Exceptions, because Serilog does structure Exceptions by default. This package does it.

Serilog with Serilog.Exceptions. All public properties as structured data. This is the way.

I would say that having spent time ensuring that exceptions are properly detailed, and those details properly logged (1), this is correct, but is not an invariant that makes exceptions useless.

1) shout out to https://github.com/RehanSaeed/Serilog.Exceptions