piwheels
piwheels does not currently support aarch64
Please note that piwheels does not yet build wheels for Raspberry Pi OS 64-bit.
https://blog.piwheels.org/raspberry-pi-os-64-bit-aarch64/
Note that aarch64 builds are supported by cibuildwheel (and testing too). It's slow but if you are already building wheels for other platforms (Linux x86, macOS ARM, Windows, etc.) on a CI, you can easily add aarch64 builds without a physical Pi.
Not sure if it is worth noting, but I'm using cibuildwheels + qemu to create aarch64 wheels in my project's release CI workflow. The resulting aarch64-manylinux wheels work well with Ubuntu's 64-bit image on RPi4. And as long as I keep ensuring the sdist works (which is uploaded with the aarch64 wheels to pypi), this issue is a low priority for me. I haven't tested this with RPi OS 64-bit, but I have no reason to doubt it will work just as well.
I wouldn't have been able to produce armv7l wheels in a CI workflow without using self-hosted runner(s) (which still might require 64-bit hosts). So, I'm deeply grateful this project can solve that conundrum for the RPi. Thank goodness for piwheels!
I'm using cibuildwheels + qemu to create aarch64 wheels
We just added the same for matrix-synapse: https://github.com/matrix-org/synapse/pull/14212/files
However, as you, and matrix-synapse, most Python projects produce aarch64 wheels (and upload them to PyPI) in the meantime, while nearly none does this for ARMv6/ARMv7. So it would be mostly redundant if piwheels provided aarch64 wheels as well. IMO, better to concentrate resources and development time on ARMv6/ARMv7 wheels which are such a great time and nerve saver for owners of older RPi models (or just RPi OS 32-bit installed) and other ARMv6/ARMv7 systems with Debian installed.
The linked blog post is over three years old, is there any sign of this happening? Is there anything I can do to help?
I heard from 1st hand that it is indeed planned. But I personally do not see such a large benefit, since aarch64 wheels are provided by PyPI already for most modules (as I stated above already 😅), or are you missing something in particular?