I was in China until January of this year and had the DiDi app on my phone. Have since acquired the 14 Pro... . Anyhow.

Go to:

App Store - Select your Profile Image - then an 'accounts' screen should open. Click 'purchased', ('my purchases' [only if your family]), and you should see your previous downloads, including apps not on the App Store at that current time. I just tried this and downloaded DiDi fine, and even used my old SIM card!