First AMD doesn't repair laptops or PCs. Only 3rd party manufacturer do like Asus the manufacturer of your laptop.
So I suggest you open a Asus Support ticket under Warranty and see if they need to check your laptop again for proper function.
If you can connect to the Internet and to a couple of gaming servers that does seem to indicate the laptop LAN/Wifi is working. Otherwise you wouldn't be able to connect at all to the internet if it wasn't working correctly or intermittently.
It is possible something is blocking certain websites from connecting.
If you have a VPN enabled disable it and see if that works. Same with Anti-Virus. If your laptop is connecting through a home Router then the router could be the problem.
See if you can connect via Wifi at another place that has free Wifi like McDonalds or Walmart etc. If can connect to other gaming sites that means it is your router at fault.