In your wireless info, we see this:
Cell 01 - Address: <MAC 'FLAT DX' [AC1]>
Channel:10
Frequency:2.457 GHz (Channel 10)
Quality=69/70 Signal level=-41 dBm
Encryption key:on
ESSID:"FLAT DX"
Bit Rates:1 Mb/s; 2 Mb/s; 5.5 Mb/s; 11 Mb/s; 6 Mb/s
9 Mb/s; 12 Mb/s; 18 Mb/s
Bit Rates:24 Mb/s; 36 Mb/s; 48 Mb/s; 54 Mb/s
Mode:Master
Extra:tsf=0000000012ee0ab0
Extra: Last beacon: 284ms ago
IE: IEEE 802.11i/WPA2 Version 1
Group Cipher : CCMP
Pairwise Ciphers (1) : CCMP
Authentication Suites (1) : PSK
IE: WPA Version 1
Group Cipher : CCMP
Pairwise Ciphers (1) : CCMP
Authentication Suites (1) : PSK
The channel, 10, is quite unusual to select as it’s an overlapped channel. We suspect, also because of this, that the router is set to auto channel select:
ath10k_pci 0000:03:00.0: no channel configured; ignoring frame(s)!
Here is an interesting discussion of the pitfalls of auto channel select: https://superuser.com/questions/1311149/why-do-wifi-routers-do-such-a-bad-job-of-channel-selection
Please check the settings in the router. WPA2-AES is preferred; not any WPA and WPA2 mixed mode and certainly not TKIP. Second, if your router is capable of N speeds, you may have better connectivity with a channel width of 20 MHz in the 2.4 GHz band instead of automatic 20/40 MHz, although it is likely to affect N speeds. I also have better luck with a fixed channel, either 1, 6 or 11, rather than automatic channel selection. Also, be certain the router is not set to use N speeds only; auto B, G and N is preferred.
We have worked on some cases where a space in the name of the SSID was detrimental to connectivity. I suggest that you rename the SSID to FLAT_DX or FLATDX or some such.
After making these changes, reboot the router.
Next, I recommend that your regulatory domain be set explicitly. Check yours:
sudo iw reg get
If you get 00, that is a one-size-maybe-fits-all setting. Find yours here: http://en.wikipedia.org/wiki/ISO_3166-1_alpha-2 Then set it temporarily:
sudo iw reg set IS
Of course, substitute your country code if not Iceland. Set it permanently:
sudo nano /etc/default/crda
Change the last line to read:
REGDOMAIN=IS
Proofread carefully, save and close the text editor.
Is there any improvement?