This is the important bit. C4 in its entirety isn't useful to many orgs and teams, and can be unnecessary overkill. You might end up picking 1 or 2 layers for yourself.

You don't have to stick to their software either, use DrawIO if that's what you prefer, but understand the main concepts that C4 is trying to impart about the separation, what goes on the arrows, and how useless icons can be.

> Take the parts that work for your team and scrap the ones that don't.

Precisely. Any time someone utters the descriptor "best practice", at best, you do yourself a favor by examining it with a critical eye and judge whether it is a good practice to follow (and a good fit for your project) or not. At worst, you beat back the consultants framing it as "the one and only way to do things (with the implication that everything else is wrong)."

The voice of reason always comes from the trenches.