Would you count scope expansion as more than just asking the team if i can build 3 extra features that are related to the original project?
I am interpreting it as way more than building those 3 extra features beyond what the scope of the project is. And even if i do that, it might even be a net negative unless it really matters.
My understanding is it has a larger area. It can also be building monitoring or alerting tools as part of my project, or even doing some janitor work on the surrounding code, or even addressing areas that got missed when the plan was put in place.
Am I on the right track?
The confusion is stemming from the idea that cleaning up gaps seems like a walk of shame due to rework, not a true scope expansion.
If you convince the team to do more work than was originally planned out, you are by definition expanding scope.
In terms of what to expand scope with, that's a trickier question. The things you mentioned all sound like reasonable scope extensions and is actually the more "responsible" type engineering work I enjoy (we called this work "Better Engineering" back at Meta).
I don't think asking to refactor the code or adding alerting is a "walk of shame". I think what would be awkward is if you realize that an entire feature is missing or there's a massive security vulnerability or something, and you are bringing it up when the project is almost out the door (or is already launched).
I think this course can help out here too: System Design Masterclass: Shipping Real Features To Production