Let's leave it on an opinionated "many=more than one" comment and everyone's happy 😬.

Can't remember or cite all the articles I read before writing mine. All talk about signals as the new reactivity approach for Angular, some of them showing how for eg BehaviorSubjects wouldn't be required anymore, some articles even show a signals implementation vs a RxJS one (most of them use a counter as an example or number addition, bet you've read those).
RxJS is the reactivity de-facto in the current Angular version, so bringing a new challenger to the playground will make some devs believe everything can be solved with signals; some other articles take good care enough to clarify that RxJS will not be replaced, mainly due to the HttpClient.
Sorry I couldn't refer to a direct source for my claims/opinions on this points 😊