Dont show some vibe coded hobby scripts. Show that you know how to build software AND how software engineering works. So build a small application that that shows you understood some basic architecture principles like oo, seperation of concerns etc. Then add a CI CD pipeline and Docker Images to show that you also have thought about deployments on production systems.

That still doesn’t show operating at scale - unless the business gains a lot of users.

It shows that you understand the fundamental concepts required for scaling in the first place

“Understanding” really doesn’t mean much without experience with actually working at scale.