I’m in the US, and have a very reliable connection. It’s only a few short hops from the biggest backbone that runs through the US. I typically play on the North America servers and have no issues, pings hover around 60 ms to Blizzards NA servers. I’ve also played on the EU just to test, and have practically zero issues there as well, pings to the EU servers hover around 130 ms.
While it’s easy to point the finger at Blizzard when you’re experiencing issues, their servers aren’t the problem, otherwise everyone else would be experiencing the same issue as well. It’s more likely that there is some sort of routing issue somewhere between your computer and Blizzards servers. Blizzard doesn’t own the entirety of the internet, so flakey points that exist on the massive web of connections aren’t their fault…
Is there a way you can try a different internet service? Maybe take your gaming system over to a buddies house and have a lan party?
One thing about Diablo 2 that IS Blizzards fault is the crappy netcode of the game, which basically has zero tolerance for any amount of packet loss and excessive ping jitter. Any amount of packet loss and excessive ping jitter will eventually result in being dropped from the game. The higher the amount of ping jitter/packet loss, the more frequent the disconnections are up to the point where it’s impossible to play.
Next time when you’re experiencing an issue with a game or a service, if you want to know if it’s just you, or a massive amount of people, check https://downdetector.com/