Good suggestion.
For anybody that it's helpful for, I've found that it's specific 5GHz channels that are affected. If you are able to change the 5GHz channels your access point uses, you can find one that doesn't disconnect for you (my Android Auto wireless hasn't disconnected when using Channel 165).
I've submitted an issue here: https://github.com/GrapheneOS/os-issue-tracker/issues/3944
After further testing, I'm almost certain this is related to the 5GHz band. By changing my home WiFi network to be 5GHz-only, the disconnects happened every minute, with it set to 2.4GHz/6GHz, no disconnects occur.
My guess is the inconsistency we've seen is because if you have an access point broadcasting multiple frequency bands, it'd depend which one you were in as to whether or not you get disconnected.
This would explain why wireless Android Auto always disconnects, because it forces 5GHz. If we also assume that mdapa's university enterprise gear was 5GHz and their old phone hotspot was 2.4GHz then that's also explained.
MAC settings also made no difference to whether I was disconnected or not, the frequency band was the only thing that changed the outcome.
I'm also now going back to wondering if it's frequency related. Most of my testing before was on a joint 2.4/5GHz network, so I would have been on 5GHz. My wireless Android Auto box is also 5GHz-only. So it might be worth disabling 2.4GHz/6GHz on a network and seeing if it has the same issue.
mdapa any chance your university network is 5GHz and your hotspot 2.4GHz?
To add to the above, using the same WiFi network as yesterday, I'm now seemingly not getting dropouts with MAC randomisation set to any of the three settings. I'll update if Android Auto is the same (so far that has consistently dropped out every minute every time I've tried), but it would appear whatever the bug is, it can be inconsistent.
Hmm okay I don't think it's 2.4/5 related, as on a 2.4/5/6GHz Wi-Fi I've had 20+ minutes without a dropout.
Interestingly, though, it seems to have dropout constantly when per-network MAC address randomisation is on, rather than off. So I wonder if it's actually a bug in this? Wouldn't explain why Android Auto is dropping out though as it's on by default. I'll investigate further.
The problem I'm experiencing is on every Wi-Fi network I've tested it with. I first noticed it because the wireless Android Auto setup I use would cut out every minute, but every other Wi-Fi network I've tested has been the same.
The only way I noticed was by monitoring the network traffic from a Wi-Fi router to the device and seeing the device fall off the network every minute. If the device has another method for internet (i.e. cellular data) then it shows the 4G/5G symbol, otherwise it continues to show the Wi-Fi symbol as it drops out for such a short time that the Wi-Fi symbol does not disappear.
So far all Wi-Fi networks I've tested have been the same, so it's interesting to hear a hotspot connection works. I wonder if it's something to do with using a 2.4GHz vs 5GHz, perhaps?
de0u I have the same issue with the Pixel 9 Pro XL, and I can say that for me it's happening with all Wi-Fi networks and the "Use per-network randomized MAC" has not solved it. Nor has a network or factory reset - it drops out seemingly exactly every 60 seconds for me. I will try reverting to stock OS this weekend to see if that has the same problem to rule out a hardware issue.