There are a number of people actively pushing ARM support forward.
If ported to ARM it could become quite a thing in embedded development. I'm not thinking about the latest Macs (although... why not?) but rather very small and cheap embedded boards where Linux could be either too resource hungry or overkill.
On these small boards a very light GUI oriented OS like SerenityOS and a set of gfx libraries and primitives could be the right tools to make appliance control panels, instrumentation, etc, and of course general computing.
It would basically be what QNX could've been (and almost was).
Yes and, most importantly, Open Source.
If you have the time, that might be a good project!
I believe it works on aarch64, there's even a raspberry pi target. Don't know the state though.
After reading this I clicked through to their Discord and it's reached the point where it's crashing QEMU on the host, and discussions are from October 1st.