Maybe some difficult 1080p videos, but my phone can handle 30 FPS ones from what I've tested. It depends of course if you require NO dropped frames, or simply not noticeable performance degradation. I can't tell when it drops one frame out of a thousand
Anyway, this point might be moot because dav1d has released several versions with further NEON optimizations after the paper
https://code.videolan.org/videolan/dav1d/-/tags/1.1.0
https://code.videolan.org/videolan/dav1d/-/releases/1.2.1
https://code.videolan.org/videolan/dav1d/-/releases/1.3.0