On the other hand, I can't quite replicate her search. When I search, I get more results than she does, maybe not as many as I'd expect, but importantly, not the same as her. I can't say "obviously there's nothing here" but I also don't think there's a smoking gun.

If you're concerned about this, you really should not be pointing me to one tweet by one user. You should have reams of evidence, documented, with a timeline, with comparisons to what other users see, etc, etc. If you don't care about convincing people who haven't already bought in, that's ok, but if you do want to persuade, you're going to have to provide something better than this one tweet. (Case in point, downthread, we have a person who's convinced they were shadowbanned, then all of a sudden they check, and they aren't: https://news.ycombinator.com/item?id=12935624).