Well, that is from 2020, according to their reference: https://en.wikipedia.org/wiki/IBM#cite_note-196

And the reference is from IBM itself. So how can we be sure it isn't just PR?

One example: one of the countries with the largest population and thus an incredible large domestic market is China. When they do anything (or the government steers the industry to do anything) they often do it at a scale not known in the already developed world.

And now the west is withholding certain technology from China since it seems to be aggressive as well. Not as aggressive as Russia or the USA, but still. So they don't get various technology anymore. But so far all I know that one level in the chinese Huawai development center could host more researches than IBMs Zürich lab. Could. Not does.

And as a consequence they bumped out their research in this area.

And now my assumption: knowing how large-scale things in China are often done, I guess that they do their industrial research equally in a large scale. So I wouldn't wonder that e.g. Huawei has by now a larger research division than IBM.

The archived article from IBM mentions 3000 researchers. That's not THAT much. Just one of the 4 german institutionalized research agencies (Fraunhofer, Max Planck, etc) has more researchers. For me, it's not unthinkable that a big chinese company has 4000 researchers by now. Especially since they HAVE to research/steal key technology these days.