The article (nor my comment) doesn't say that AV1 can't do multithreading. What the article at texpion says is that it can't make CPU cores sustain hight loads the same way x264/x265 does.
That said, I have no idea whatsoever about video codecs; I'm just saying what I understood from the link I was provided with.
dav1d can make use of the CPU at sustained high loads if you want it to. It can do over 30 frames a second on even a single core of an Apple A12X, and over 100 frames on an A12x using multiple cores.
That said, I have no idea whatsoever about video codecs; I'm just saying what I understood from the link I was provided with.