Apparently, it's a common problem that Chrome and other Blink-based can no longer scroll using the mouse wheel. This happens across OSs. The fix people usually post is to disable smooth scrolling. That didn't work. But what did work is switching the display server from Wayland to X11.
There's a command-line switch for Blink browsers to use Wayland when you're in a Wayland session. I don't know what it is otoh. I assume that'd also work.