Yes and no. As with most things, it’s more complicated than that. While it’s true that not many philosophers would claim to be “pure” nihilists, instead opting to qualify their position, there are nihilists who do have a very doomer outlook so to speak.

This is why in the article you linked, nihilism is qualified as “optimistic”. This kind of nihilism is often associated with Nietzsche and later as your article mentioned, Sartre. Though I’m not sure Sartre would say he was a nihilist; Sartre was a huge figure for the existentialists. However, the two movements have a lot in common and one could argue that optimistic nihilism and existentialism are close enough to be considered the same thing. I am aware of some scholars who consider, for example, Nietzsche to be an early existentialist. It must be noted, however, that the optimistic qualification is of utmost importance. Nihilism says flatly that there is no meaning, existentialism says that we are able to decide what is meaningful.

Anyway, this is all to say that Nihilism (with a capital N) is a pretty pessimistic and “doomer” idea to have. Nietzsche himself argued that the solution to nihilism was to destroy all interpretations of the world so that we can start from zero and hopefully realize some actual meaning. Perhaps my understanding of doomer is wrong, but from where I’m standing, nihilism and doomerism are pretty much the same thing. Different flavours of nihilism will produce different conclusions about this connection.