I recently decided to try Linux, and I started with Zorin OS on dual boot. I installed the wrong drivers accidentally for my Archer T2U Nano (I need the rtl8821au and installed rtl8812au instead). I then removed them and installed the correct ones and it worked flawlessly. A few days later I decided to stop using Windows completely and so I formatted and reinstalled Zorin. I installed the correct ones straight up, but for some reason only 2 out of 8 networks show up, which both happen to be 2.4GHz, but I can't use my 2.4GHz network because I'm pretty far away from the router and it goes really slowly. I've seen some people say that it's probably a router settings related problem, but it doesn't seem to be because in my case no 5GHz networks show up and anyway I don't know the password to change them nor if there's any important setting that was changed so I don't want to reset to default settings, at least not yet. Also, sometimes I can't connect to any network at all. I think this happens when I unplug and replug the adapter, and it fixes itself after rebooting. What should I do?
Edit: I managed to find the router password, and I changed the settings to the recommended here: GitHub - morrownr/8821au-20210708: Linux Driver for USB WiFi Adapters that are based on the RTL8811AU and RTL8821AU Chipsets - v5.12.5.2.
Now I can connect to it, but the speed is really inconsistent and slow, peaking at ~20Mbps. Even if I'm far away from the router (literally one floor above it, it's surprising it even reaches here with no extender), my phone gets a lot higher speeds, around 80Mbps (which is what I used to get on Windows), and even using another adapter (which I don't want to use because it doesn't detect 5Ghz networks) gets 35Mbps on 2.4Ghz.
You should definitely make a report about this issue in the GitHub repository. It looks like this driver is well on its way of becoming part of the kernel, and the maintainer is looking for feedback and testers. Not only would be helping with that, but the support you'll get there will be much better.
And if you do manage to get things working, please report back!
It works now. What I had to do was set the band width to 80MHz and switch the channel in the router settings (because there were 8 networks in the same channel, and thus a lot of congestion) and it actually started working at the speed we're paying for (which it never had before), and it works at half the speed on my adapter, which is still pretty good (and more than I need) for how small it is and how far away from the router I am. I believe the signal was too weak to even find the network, and now it's a lot stronger.