I have to constantly restart NetworkManager (or run sudo modprobe -r iwlwifi && sudo modprobe iwlwifi - effects are indistinguishable) on both of my Ubuntu devices to deal with constant sudden losses of access to the internet when I'm connected to my home network. I even started keeping a dedicated terminal tab just to re-run sudo systemctl restart NetworkManager again and again.
0) All of the affected devices are running Ubuntu 20.04.4 LTS.
1) I have a main router at home and a repeater in my bedroom (because, when the door is closed, the main router becomes unreachable to Some of my devices).
2) The main router offers a single 2G network, while the bedroom repeater repeats the main router both as a same-named 2G network and as a alt-named 5G network.
3) The problem I will describe has never happened to my Android phone, but it does happen to both my Ubuntu desktop computer and my Ubuntu laptop.
4) It makes no difference whether I connect to the router or the repeater or which one I'm closer to. Only the problem is considerably less frequent (hours vs minutes) when I'm connected to the main router (but it does still happen).
5) It makes no difference whether I connect to the repeater's 2G or its 5G.
6) The exact same pattern shows up when I connect to either the router or the repeater via Ethernet cable.
7) My internet provider has replaced the main router in the meantime since the pattern begun (for other reasons) and, essentially, nothing changed.
8) The problem doesn't happen to my Ubuntu notebook when it is connected to other networks (even when for many hours).
9) Restarting either the main router or the repeater or restarting the devices themselves all have the same observable effect as restarting the NetworkManager: internet connection is back for a while, but the pattern persists and soon i lose my connection to the internet again.
10) The loss of connection doesn't affect one device necessarily at the same time it affects another.
11) Changing the wifi adapter (I have 2 USB adapters) changes nothing.
12) Factory-resetting the repeater and minimally re-configuring it to repeat the main router also doesn't change the pattern.
13) Turning off the repeater doesn't zeroes the recurrence of the problem with the main router.
14) Both systemctl and modprobe methods show the same observable effects.
15) The connection to the network itself remains when the problem happens. Only thing affected is connection to the internet.
16.1) One device is is a i5 / 8gb RAM desktop PC with a 500W PSU and no power saving feature enabled at all, usually connected to the repeater via ethernet (but it doesn't matter, as tested and already detailed above).
16.2) The other device is a i7 / 16gb RAM Samsung X50 notebook, usually connected to the repeater via its internal wifi hardware (Intel Wireless-AC 9462) (but it also doesn't matter, as also tested and already detailed above). It may also be relevant to point that the problem persists on the notebook even with no peripherals connected (I'm aware that they may drain energy and affect wifi performance).
17) All that said, the problems manifests in the exact same way in both devices, and Only between them and my home networks (I connect my notebook to other networks almost daily without any problem, I also have 2 Android devices which have never been affected, and other people connect their own whatevers to my home networks and no one has ever mentioned any connectivity issue), so that Ubuntu 20.04.4 seems to be the only factor unifying the affected devices and excluding all the unaffected ones.
