I don't think the surveillance system got much more sophisticated but for anyone wondering what china's surveillance system was like before the pandemic, I stayed in China three times for a total of about a month and a half in the 6 months before the pandemic.
When you get to the airport, you will likely notice the abundance of cameras, including paths which take you right under overhead cameras. Your photo will be taken at the airport border control and your visa will be stamped. You will get an entry card you must fill in before leaving china and present alongside your passport. This card details the hotel you will be staying at. If I recall correctly you also had to provide these details on the visa application form, as well as a recent photo.
When riding in a car, cameras on all major roads will periodically take photos of the front of every car every few hundred meters, accompanied with a literal flash.
Once you arrive at your hotel, you will be greeted with yet another camera, you will be required to check in your passport and have your photo taken. This system, I believe, is a government integrated system as between all the hotels I visited, they seemed to have a very similar computer with a similarly mounted camera.
If you plan to travel between cities, you will need your passport to buy the ticket. Once on the bus to a different city, it's possible someone at some checkpoint will abruptly enter the bus with a hand-held camera to videotape everyone's faces.
In large cities, especially the bigger ones, cameras are everywhere, there's cameras on top of cameras pointing at other cameras. Comedic cartoons of surveillance don't do it justice.
When using the metro (underground) transportation systems you will again be passing through gates with overhead cameras pointed at your face. Presumably to match up the chip-coins (or whatever the particular metro system of the city you're in uses) with routes taken and map these to photos of your face.
If you plan on taking a taxi, expect to have to use didi or something equivalent, didi doesn't take payments via bank cards, didi takes payments via wechat or alipay. To get wechat working as a foreigner in china, you must find Chinese people who will vouch for you to activate your account (let's hope you can chat up some people in a bar to help you with this feat). To get alipay working in china, you need a chinese bank account, unless you're extremely lucky and manage to get it working without one (I managed once out of my three trips). I'm pretty sure both alipay and wechat are tightly integrated into the chinese surveillance system.
I'm pretty sure the information which gets collected would be useless if it also didn't get dumped in a centralised system and processed collectively, so I'm pretty sure there is some centralised system with complex processing.