I’ve been having similar issues. I recently am trying to get back into GW2. Got it to install initially (with some hassle). Now I’m patching 160k+ worth of files.
It starts higher than it ends, but even then starting at 100kbps seems slow – ends up stalling out at 0kbps, with usually 1 or 2 MB worth of data being retrieved before I try and restart it.
Tried the “..\Guild Wars 2\Gw2.exe” -assertsrv 151.249.89.142:80 shenanigans, and seems to help the initial burst, but ends up failing like the rest. Tried a lot of different IPs.
Using Comcast in MI (Grand Rapids area). Can post with diagnostics/specs if needed.