On my aarch64 devices, Chromium in a Docker image loads faster, never dominates the CPU, renders video and websites faster, and has working DRM. Firefox is slower in every respect and can't render Netflix.
I don't think you can make a blanket statement like this. My experience has been almost the opposite, Chrome always uses significantly more CPU for me.
I think it really depends on hardware, drivers etc.
On my aarch64 devices, Chromium in a Docker image loads faster, never dominates the CPU, renders video and websites faster, and has working DRM. Firefox is slower in every respect and can't render Netflix.