3rd Party Data - Full Removals?

Is there a way to have all data completely deleted from sites such as csrep, leetify, or csstats? In the sense that nothing is displayed anymore and no more data is collected?

I think I tried this once on csstats, but I was told that the data comes from Steam. Ultimately, however, shouldn't every data collector be able to ensure that profile data can be completely deleted? Or am I wrong?

You can't. Those sites don't track you directly.

They get data from:
- Steam Web API

- CS2 match share codes / match history

- Public Steam profile data

- Sometimes Valve official demos / matchmaking endpoints

Even if you found a way to delete it from one of the sources or whatnot, it can be always re-collected later on.