I have a 2023 mac mini (M2 Pro) in hand now, so I started experimenting, using an ASUS ET8 as access point. The short answer is that it does work, but getting the AP configured properly is really frustrating. At least with the 386.49873 firmware (which is still the latest for this model, anyway). I think the ET8's configuration GUI is actually buggy: doing and then undoing a simple configuration change got me from working, to not working, to not working, and after that nothing I did made it work again. I would probably have given up some time ago except that I did see it work for a little bit.
I ended up doing a hard reset and reconfigure from scratch, and that got me to a working configuration that I'm now quite hesitant to mess with. For the archives' sake, here's a recipe that seems to work:
* Hard reset the router (I always use the WPS-button method).
* Connect to it, choose the "advanced setup" option, run through the configuration options it gives you. I selected access point mode because that's what I need; probably router mode would work as well. When you get to the screen where you configure the SSID names and passwords, do not enable the "separate bands" option, even though it tells you you ought to. It will not at this point let you set the 6GHz band SSID name the same as the others; just ignore that for the moment, and make sure the lower bands have the name you want, and that the same password is used for all.
* After it reboots, reconnect to it and finish up any other admin settings you want, not touching any wireless settings yet. Then turn on "ethernet backhaul" mode in AIMesh -> System settings.
* At this point it should be in "tri band smart connect" mode and advertising only one SSID for all bands. This is what you need to get it to talk to Apple gear. AFAICT it will not work without smart connect ON and wireless backhaul OFF; otherwise it seems not to broadcast the RNR packets that Apple needs to see, and/or not use the same SSID name across all bands.
The only additional wireless configuration I've risked changing is to cut the 2.4GHz bandwidth setting from 20/40 to 20MHz only, and force a particular 2.4GHz channel setting, because its default behavior tends to want to straddle multiple standard channels, which is not a great idea where I live.
Also, if you had any previous failed attempts to connect a given piece of Apple gear, telling it to "forget this network" and then re-join and re-enter the password seems to be helpful. For me it initially sort of worked without that, but then I noticed that System Settings -> WiFi was claiming that the AP was broadcasting a different SSID name for 6GHz. I wondered if I needed to do something weird in the AP's GUI, but turned out that "forget this network" cured that.
Anyway, the good news is it works. The bad news is that performance seems seriously erratic, at least as measured by iperf3. I'll just quote one iperf3 run to show you what I mean:
[ 5] 0.00-1.00 sec 182 MBytes 1.52 Gbits/sec
[ 5] 1.00-2.00 sec 194 MBytes 1.63 Gbits/sec
[ 5] 2.00-3.00 sec 195 MBytes 1.64 Gbits/sec
[ 5] 3.00-4.00 sec 190 MBytes 1.59 Gbits/sec
[ 5] 4.00-5.00 sec 189 MBytes 1.58 Gbits/sec
[ 5] 5.00-6.00 sec 197 MBytes 1.65 Gbits/sec
[ 5] 6.00-7.00 sec 74.6 MBytes 626 Mbits/sec
[ 5] 7.00-8.00 sec 16.7 MBytes 140 Mbits/sec
[ 5] 8.00-9.00 sec 11.7 MBytes 98.1 Mbits/sec
[ 5] 9.00-10.00 sec 8.57 MBytes 71.9 Mbits/sec
I'm testing using a 2021 Macbook Pro -> Ugreen 2.5G USB/ethernet adapter -> ET8 WAN port -> wireless -> mini. I know from past testing that the MBP+Ugreen adapter can push close to 2.5Gbps, so that's not the bottleneck. With no other 6GHz gear at hand, I can't tell whether the ET8 or the mini is more at fault for the performance issue. It's not good though. This is under basically ideal conditions: AP and mini about 15 ft apart with clear line of sight, and I'm pretty sure none of my neighbors are using 6GHz yet. But either there's some bad interference somewhere, or Apple and/or ASUS have a lot of optimization work yet to do.
(Addendum: in the time it took to compose this post, the performance seems to have stabilized a bit, now averaging around 1.5Gbps to the mini and 1.15 from it. Maybe this hardware has some kind of learning/adaptation curve, or maybe the interference stopped for now? I'll keep an eye on it.)
