Network issues~ How will you resolve them? Who should I contact? The Xfinity assistant bot is not smart enough.

I can't access Battle.net China, World of Warcraft China, Wuthering Waves China, and other games today. they all shows a network connection timeout.   everything was working fine yesterday but today are not. Additionally, when testing China's network nodes, the ping value has become extremely high, and there's severe packet loss. But the most interesting part is that when I share my T-Mobile mobile network with my laptop, all these issues disappear.