WiFi quality degrades too much

[xNix]

Since I've got my Pinebook Pro this problem keeps haunting me. WiFi gets really bad on negligible distances and obstacles.

Here are some speedtests I've just did:

Code:

Test 1 (far):
Download: 1.94 Mbit/s
Upload: 3.24 Mbit/s

Test 2 (middle):
Download: 6.01 Mbit/s
Upload: 16.17 Mbit/s

Test 3 (closest):
Download: 42.00 Mbit/s
Upload: 48.58 Mbit/s

The first test is done at 5 meters distance with 2 solid concrete walls and my back that block the WiFi signal.
The second test is done at ~2 meters distance with the same walls blocking it.
The third test is done with the laptop on top of the router.

This is based on the 2.4GHz band. Now one would say the walls are the problem, but if I do the test with my smartphone at the very same place as I did the 1st test, my speeds would reach ~30Mbit/s. So apparently the walls shouldn't cause that much of a problem. Just to make sure, I took another laptop (Acer TravelMate B117), placed it on the very same place as my Pinebook Pro in the 1st test, ran a speedtest and the speeds were the same as my phone - ~30Mbit/s.

The conclusion is that my Pinebook Pro is the problem and not the router or the location. I just can't figure out whats wrong. I've changed distributions, changed the firmware drivers, tried everything in the Wiki about problematic wifi, nothing fixes the issue.
Is it antenna problem? Firmware problem? Something I'm missing?

Just for the sake of completeness, I'm running on Manjaro ARM 20.04 right now. This is the firmware I did my speedtests with:

Code:

# pacman -Ss ap6256 
community/ap6256-firmware 2020.01-1 [installed]
    Firmware files for the ap6256 wifi/bt module

Edit: This should be quite useful as well:

Code:

Test 1 (far):
wlan0     IEEE 802.11  ESSID:"Anonymous" 
          Mode:Managed  Frequency:2.462 GHz  Access Point: 0F:0F:0F:0F:0F:0F  
          Bit Rate=6.5 Mb/s   Tx-Power=31 dBm   
          Retry short limit:7   RTS thr:off   Fragment thr:off
          Encryption key:off
          Power Management:off
          Link Quality=32/70  Signal level=-78 dBm 
          Rx invalid nwid:0  Rx invalid crypt:0  Rx invalid frag:0
          Tx excessive retries:60  Invalid misc:0   Missed beacon:0

Test 2 (middle):
wlan0     IEEE 802.11  ESSID:"Anonymous" 
          Mode:Managed  Frequency:2.462 GHz  Access Point: 0F:0F:0F:0F:0F:0F   
          Bit Rate=52 Mb/s   Tx-Power=31 dBm   
          Retry short limit:7   RTS thr:off   Fragment thr:off
          Encryption key:off
          Power Management:off
          Link Quality=40/70  Signal level=-70 dBm 
          Rx invalid nwid:0  Rx invalid crypt:0  Rx invalid frag:0
          Tx excessive retries:154  Invalid misc:0   Missed beacon:0
         
Test 3 (closest):
wlan0     IEEE 802.11  ESSID:"Anonymous" 
          Mode:Managed  Frequency:2.462 GHz  Access Point: 0F:0F:0F:0F:0F:0F  
          Bit Rate=43.3 Mb/s   Tx-Power=31 dBm   
          Retry short limit:7   RTS thr:off   Fragment thr:off
          Encryption key:off
          Power Management:off
          Link Quality=70/70  Signal level=-11 dBm 
          Rx invalid nwid:0  Rx invalid crypt:0  Rx invalid frag:0
          Tx excessive retries:154  Invalid misc:0   Missed beacon:0