Very high latency issues


Is it just me, or others too are experiencing extremely high latency often?
I play on Mirage Raceway (Normal, Classic) and sometimes I have a normal 40-45ms latency. However often it goes as high as 4000ms! This makes it impossible to progress. I tried every method one can think about:
-Deleted WDB, Cache folders (and disabled addons)
-Disabled “Optimize for high speed” network option (it was enabled by default)
-Enabled IPv6
-Tried restoring stuff in windows, flushing the DNS, installing the latest drivers
-I even removed Avast! in favor of Windows Defender (I’m on Windows 10 x64)
-Of course I also rebooted my network devices multiple times.

I have it set-up the following way:
Direct gigabit fiber to the home -> Huawei ONT (which connects me to the internet) --> TP-Link router which is only working as a switch, the wan port isn’t used. Need this setup to share the internet connection. Only wow was running on my computer and only web browsing on the other, so no torrents or any high bandwidth stuff.

I can’t think of any other possible issue. Everything else is lag-free for me, discord works perfectly when used, only WoW lags, but it does so in a way it becomes unplayable.

Any ideas, suggestions?

Last time I did reboot both my network devices, uninstalled avast and disabled the optimize for high speed option. I don’t know which of those did the trick, but I could play for about half an hour. Then it came back…

Depending on where you can be a fault with the fiber cables we in South Africa have the same problem now with to of the submarine cables being damaged now ther is only 1 left for the entire county