Found a solution. It used to be (pre iOS 13) that you could grant Health access to multiple apps from one screen in Privacy-->Health. But now, you need to go into each individual app you wish to connect to Health and poke around until you find the "Connect to Apple Health" (or a similar name) setting. Once you find that, allow it to connect to Apple Health. You have to do this for each app, one-by-one! For example, go into Aaptiv and turn on Health access. Then go into Cronometer and do the same thing. Then EufyLife, etc etc.
Once you've done this, all of the apps and their health access settings will appear the way that they used to do in the Privacy-->Health tab. (I don't know if this was a 13.1 change, or if 13.0 also worked this way, but I didn't figure it out until after installing 13.1)