Notebook Wireless and Networking

New laptop, and since the beginning problems with wifi.

Every other device in my house works perfectly well with our wireless wifi.

But this laptop seems to have some trouble: every now and then, while browsing, the internet connection seems to get lost, although the icon in the right bottom corner shows no problems with the wifi. This happens randomly: sometimes a few times per day, sometimes every 5 minutes, and sometimes not at all.

When I run the built-in Windows Network troubleshooter or the Chrome extension HP Network Check, it always describes the same problem: "The default gateway is not available."

Tried potential solutions so far:
1) Run Windows Network troubleshooter or HP Network Check - it fixes the problem, but it comes back.

2) Uncheck the box for "Allow the computer to turn off this device to save power" - No impact on problem.

3) Update/Rollback/Delete (& Reboot pc) the following drivers: "Realtek RTL8822BE 802.1ac PCle Adapter" and "Realtek Gaming GbE Family Controller" - No impact on the problem.

4) Shut down & restart the WiFi driver "Realtek RTL8822BE 802.1ac PCle Adapter" - fixes the problem for a while but it comes back

What can I do to solve the problem permanenlty?

Thanks in advance.