Most people don’t enjoy red badges. I certainly don’t.
Some Figma files that I work in have many, many comments that are unrelated to me, yet I still need to go through each one to remove the red badge on the comments icon.
It should be possible to mark all comments as read, to make this process less tedious and distracting. Forgive me if it already is!
The only way you could do this is by going to the homepage of your Figma app, opening the notification pane, and there you’ll have a Read all button.
There’s no other way, just this, which affects all the projects, not just a particular one.