My hot take is that React doesn't directly _cause_ slow performance, but that React is so well marketed as a first place to start for new programmers that the bar for quality is much lower than other industries (like game programming, or even "vanilla JS" which is increasingly seen as an advanced approach).
Another app that I'm not sure if it's React or not is New Reddit. It is significantly slower on my computer and on a lot of people's computer and sometimes you have to refresh the page because it consumes too much memory.
I can come up with other local examples, from Germany. Vatenfall's website seems to "traditional" page navigation, but the content is loaded via a framework. Due to having to reinitialize everything, text takes up to 5 seconds to appear when using the back button or when navigating for page to page. Similar things happen in the German Agentür fur Arbeit.