Wifi keeps disconnecting from laptopt and pc running on Ubuntu 18.04 / 20.04

I have problems with my wifi and Ubuntu usage. Once I connect to the wifi, the wifi connection keeps dropping and disconnecting. A ping www.google.com shows no connection. In some cases, restarting works but in others it is just impossible to use the wifi. I am having these issues on my laptop (running Ubuntu 20.04 LTS) and on my pc (Ubuntu 18.04 LTS). Here is the output from my pc about available wifi networks:

   description: Wireless interface
   product: Wireless 8265 / 8275
   vendor: Intel Corporation
   physical id: 0
   bus info: pci@0000:04:00.0
   logical name: wlp4s0
   version: 78
   serial: 14:4f:8a:cd:ea:24
   width: 64 bits
   clock: 33MHz
   capabilities: pm msi pciexpress bus_master cap_list ethernet physical wireless
   configuration: broadcast=yes driver=iwlwifi driverversion=4.15.0-147-generic firmware=34.0.1 ip=192.168.0.136 latency=0 link=yes multicast=yes wireless=IEEE 802.11
   resources: irq:136 memory:f7000000-f7001fff

On my laptop, the vendor of the network card is also Intel. The other devices (MAC and windows) don't have any issues with the wifi, so it is Ubuntu related.

I know there have been several posts about this issue, and I have read them all, but none of the suggestions did work for me or solved my problem. But in most cases there I noticed a connection to the broadcom network card.

Has someone any idea what could I try to solve this issue?

Your wireless may be dropping because of power management; that is, the feature where the card partially powers down to save battery power during periods of inactivity and then, ideally, powers back up seamlessly when activity resumes. Let's disable power saving to see if it helps. From the terminal:

sudo sed -i 's/3/2/' /etc/NetworkManager/conf.d/*

Your wireless may be dropping because the channel to which it was connected has suddenly changed.

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 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.

Your wireless may be dropping because there are two wireless access points with the same name and password. This is typical when you have a 2.4 gHz segment and a 5 gHz segment of the same router. Your wireless may be roaming, looking for a better connection. If this is the case, I suggest that you rename the access points; something like myrouter2.4 and myrouter5.

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?