My experiences before was that they were doing some machine learning to detect my socks proxy and slow it down eventually. Last visit I went to China a few months ago I found my Wireguard VPN running at full speed.

Either technology has improved or they stopped trying as hard, which makes sense now that the local internet economy has matured.

I was never good at VPNs. We would find one that worked, they wanted a one year subscription up front and...then they would stop working. I assume most VPNs in China are just a scam to make some shady money. Who are you going to complain to, the Chinese government?

China would try to block them so you had to find new alternatives. I used one for years that stayed up, but yes it was often frustratingly slow. You had to really make an effort, and most people aren't going to do that, and then there's the language barrier.