You have done a very good job using Mathematica PingTime and HTTPRequest functions. I am wondering if you had any issues within the academic institution, are you working there as a researcher, or if you are a student, how did you explain your curiosity. It's a sensitive topic there, and to run those scripts through university network were there any issues with that?

I am actually working on something similar myself as a part of an academic program, started with social media domains as these have been known to be very restricted, especially during this year, I got a lot of help from Gilbert

However, I'm not physically located in China, so I have to use a commercial VPN instead. I tried a few of options from this research but it's quite tough to get a stable connection, and not to mention a proper speed. I finished a few tests already in May but having the same problem as you have - scaling.

I wonder if you have already set up a private Chinese server by now and extended the research. If yes, would you mind sharing those results?

Please PM me if you can, I would be very open to sharing my work and ideas with you (privately).