How to visualize a system architecture using the C4 model?

Good point. I used a 'system' as a synonym for a 'software' but you are right that it can be confusing

The C4 model also includes an optional deployment diagram (kinda like the deployment diagram from the 4+1 model). You could indeed use the abstractions of your cloud provider to draw that but I think it's more helpful to use C4 abstractions. Since this allows you to map concepts from your software (C4 containers) to your infrastructure.

Let's say to have a reasonable complex (micro)services landscape running in the cloud. I would create:

- one context diagram. System as a blackbox with surrounding actors.

- one or multiple container diagrams. One per bounded context.

- one deployment diagram mapping out the most significant cloud infra, their interrelations AND some example C4 containers to show how the software maps to the infra.

Making different diagrams to show different concerns is exactly what to do [0]. Trying to show everything in a single view is impossible, you'll just make a mess.

[0] Ilograph calls these different views perspectives: https://app.ilograph.com/demo.ilograph.Ilograph/Request Full disclosure: I made this

Have you checked out flows in https://icepanel.io for sequence diagrams?

Is this the same package used in structurizr.com?