Sure there are, it's called brcmfmac. If the AsahiLinux team hasn't already got it working, certainly Corellium did a few months ago in their much hyped public demo image.

https://wireless.wiki.kernel.org/en/users/drivers/brcm80211

OpenBSD has also added support to their bwfm(4) driver already for 6.9.

Wireless is absolutely not the hardest problem for the M1 Mac, or running on any Mac, for that matter.

Broadcom Wi-Fi languished for something around a decade under the "b43" driver before Broadcom showed up with their brcmfmac driver, it caused significant anger within the kernel community that they decided to write a new driver instead of just augmenting the existing one

They have various product families and more than 2 drivers.

I need the bcmwl driver (dkms) for some 4-5 year old HP laptop and it has severe problems with some APs and slight problems with others. Overall it's just bad.

Debugging it showed that it's only a thin Linux wrapper around some huge binary blob they use. So not really FOSS, but of course that's what we are used to with firmware. This was't really firmware, they use the blob on the CPU IIRC. (It's been years I debugged this, since then Broadcom is just something that raises a red flag to me.)

Usually it's missing firmware rather than drivers.

Genuinely curious, is it harder than getting Linux working with the proprietary Apple variant of ARM? Or are you talking pre-M1?

The M1 still uses a broadcom wifi chip: https://news.ycombinator.com/item?id=25669358, so presumably because it's a newer chip it'll be more difficult.