If cancellation involves abandoning server-side state, then calling an explicit action on the server could make sense. Buttons submit forms (aka mutate state on the server), links navigate to resources.

HN gets itself twisted into a knot over web dev "best practices" and tries way too hard to put things into certain ontological boxes. I would not overthink this. Empathize with the user and follow the vibes if you want a good UI/UX. Explore the nuance of the design space. Maybe buttons sometimes work for pure navigation too.