I just realized that Didi China is a separate app from Didi outside of China. I had the latter installed from my trip to Costa Rica a few weeks ago, but it didn't do me any good in Suzhou. Fortunately, Didi can be booked within Alipay, Wechat, and Amap, but I personally prefer avoiding the mini apps when possible, as they seem to be giving me more issues.
Overall, my experience is much better than my last trip to CN in 2018, thanks to everything moving to app-based purchasing. But definitely do what you can to get verified before traveling, as it feels like a neverending process for both Wechat and Alipay.
Another headache was when I tried to book a Didi at Suzhou railway station, from the clearly marked rideshare area. Apparently, there are several very similar-sounding Didi pickup spots in the same general vicinity/side of the station, as it turned into a royal PITA (I had the same issue at both the north and south exits).
I'm finally starting to regain some of my sense and sanity, but the first 24 hours in China can be quite bewildering and frustrating for a wide variety of reasons. I still have absolutely no idea how to order food at a restaurant. The first 10 I walked past near my hotel all have the menu on the wall behind the counter, so my typical approach of using Google translate and then pointing to what I want on the menu isn't an option. The last restaurant I went to only had their menu on a single tablet, which was probably more annoying, but at least I could select what I wanted. I really miss Japan and their gorgeous meal mock-ups. Fortunately, I will be heading back there in a few days.