The same problem persists on android 10, but I just found out if I connect to a VPN on my computer (not on router), I can surf the web normally and the problem goes away. Once I disconnect from the VPN the same problem comes back again.

To clarify more on the problem that is happening, pages keep loading indefinitely or load extremely slowly, however apparently pinging for example 8.8.8.8 or google.com still works for some reason. I have also tried USB tethering using a different sim from another provider but the same problem persist (tethering is allowed with both providers so this shouldn’t have been an issue anyways). A regular mobile hotspot from my phone also works perfectly fine.