[knorker]

Good luck. If you find a reliable way to find them then please shout that far and wide.

I tried about 10 different wifi usb dongles and all but one were completely unsupported or unusably unreliable (as in 5-10% packet loss, and sometimes needing unplug/replug) on OpenBSD.

All the guidance I found was "just get one with this chipset". But it's not that simple. It's usually not listed on product pages, so you have to guess.

And even the ones that do have the right chip can be very unreliable. Granted, most that I tried were super cheap. But those super cheap ones worked fine on Linux.

In the end I found one that worked properly with OpenBSD. Old and unbranded, so it wouldn't even help you.

I don't think there's a single 802.11ac USB dongle with free drivers. On Linux there are separately downloadable kernel modules, but I've found that to be a nightmare not necessarily to get working, but to keep working across kernel upgrades.

So my suggestion is to look at supported chips, try to guess which products have that chip, and buy a few. Hopefully one works.

[Fnoord]

dkms helps with keeping a module working across Linux kernel upgrades (I use RTL8812AU, but RTL8814AU is problematic [1] being broken. I also use dkms + ZFS on Proxmox and Ubuntu), but other than that don't upgrade Linux kernel, unless you have to. I guess OpenBSD doesn't include the binary blobs, but back in the days (about 10-15 years ago) I used to have a stable WLAN on OpenBSD, on a Soekris. This was 802.11n (later rebranded WiFi 4), I don't now about 802.11ac / WiFi 5. Worked perfectly fine. IIRC it was either Atheros or IWL.

[1] https://github.com/aircrack-ng/rtl8814au