How to change the default kernel Wi-Fi driver?

IN-USE BSSID SSID MODE CHAN RATE

•   xx:43:63:B0:7C:xx  POJA-F-2.4G               Infra  7     130 Mbit/s  >
  

I doubt that you selected channel 7 for your router as it is an overlapped channel. https://www.metageek.com/training/resources/why-channels-1-6-11/

I strongly suspect that your router is still set to factory defaults; however, many wireless drivers, including iwlwifi benefit from fixed, not autoselect settings.

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 recommend 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. 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.

Moreover, you have a very modern wireless device that is easily capable of very high speeds that is connected to the oldest, slowest protocol; that is 2.4 gHz. I am certain that you will have much better luck connected, again with specific settings, to a 5 gHz router.