Probably multiple ways to do this.
Try this:
- override the template that invokes that helper
- substitute it for a helper of your own
Template in question: discourse/app/assets/javascripts/discourse/templates/list/topic-list-item.raw.hbs at c6e255f4e00400b8a6f82a799b7fa082b17adb1c · discourse/discourse · GitHub
Overriding a template so low in the hierarchy is relatively low risk.
Another way might be to use jQuery within an override of the topic-list-item Component to perform the modifications you need.