I've been there for a while (2 years straight and more than 6 years since my first trip), I used many different VPNs providers and even setup my own servers.

Although the company is a bit shady and I'm pretty sure they have some connection with the party, Astrill is the best to use in terms of performance, bandwidth and ease of use. They recently added WireGuard support which is blazing fast.

However, if your priority is privacy, probably you should use your own server, or just stay out of China.