You can get TKO'd on the feet if you're unsteady after a standing eight count (that part in the movies where they count after the boxer gets owned (as opposed to a mandatory eight count if you get knocked down)). Doctor/team stoppage between rounds would also be a TKO. But it looks like Olympic rules are a little different, the interchangeable term, and perhaps more clear for the layman, the referee stops contest (RSC) is used[1]. It also doesn't look like there's any limit to knockdowns as long as you keep getting up. You will almost certainly at least lose by points if you eat a bunch of knockdowns and you will likely face an abandonment as your team would throw in the towel if you are just getting pummeled.

If, for the sake of argument, you get punched in the face, start crying, and decide to stop, you would get an abandonment (ABD) which is a loss by any other name.

[1] https://www.nbcolympics.com/news/boxing-101-olympic-rules-regulations-and-scoring