[Android Apps and Games] rsngfrce:
My understanding, which I am not saying is correct, is that there are two states as you say, stopped and disabled, but stopped is considered to be frozen, rather than disabled being considered frozen.

A disabled app, as you say, can't be run and it's icon is not visible. On a non-root phone, the only way to disable an app is to use ADB or an app designed for that purpose that you grant Device Owner status (which can be a pain).

I use an app on F-Droid, SuperFreezZ App stopper (Entirely freeze all background activities of apps.), which says it works the same as Greenify. I discovered that if I force stop an app, it is listed in SuperFreezZ as frozen (not disabled, as I think you misunderstood). This is where I got my impression that force stopping equals freezing and discovered why apps that I had force stopped would not run in the background until I started them again. For me at least, it was important to understand that force stopping an app didn't just stop it for "now" to release memory, but would prevent it from running until I ran it again (or restarted for apps that start on boot, I believe, but I could be confused about that)... so I have to be more careful about what I force stop, especially if I don't plan to restart immediately.

Samsung phones have an app called Device Care which tells you that you it can free up memory by stopping background apps that "haven't been used recently". These are mostly system apps that can restart themselves I believe, since they aren't being disabled, but it gives no indication that if it stops a user app, that app will be "frozen".

On my rooted phone, Titanium Backup would do what it called "freeze" apps, but that was actually disabling them I believe. So the meaning of "freezing" becomes confusing.

UPDATE: I am going to leave what I already typed above, because it illustrates my confusion over this issue. I just had something happen that I have seen happen before, but hadn't thought about enough and really confuses me.

I attempted to run an app on my phone and it kept crashing immediately. My first thought was to try to download it from the Play Store again. The Play Store, instead of giving me the option to uninstall or open it, as it usually would, gave me the option to enable it. I checked in SuperFreezZ and it was listed as frozen. Running it was not "unfreezing" it.

After I enabled it in the Play Store, an update was immediately available, so it was being kept from updating as well. This app was not disabled and was still visible in my app drawer. I have a non-rooted phone, so SuperFreezZ would not be able to disable it anyway. I checked it in CCSWE (Device Owner version) and it wasn't listed as disabled and I know I hadn't disabled it anyway.

I checked some other apps that were listed as frozen in SuperFreezZ and some gave me an enable option in the Play Store and would not run and others did not and would run.

So this is VERY confusing, but reinforces why I was thinking that force stopping an app is potentially very dangerous, unless you really want to FREEZE it.

But why does there seem to be two "frozen" states, one that won't run on its own but is still "enabled" and another which is functionally "disabled", but still visible in the app drawer, unlike a true "disabled" app?

I have attempted to ask the devs of SuperFreezZ similar questions on GitLab.

UPDATE 2: Another related question has occurred to me. The system of my Samsung Galaxy S10e phone can put apps to sleep or to deep sleep. It defines sleep as, "These apps won't run in the background. They may not receive updates or send notifications." Deep sleep is defined as, "Deep sleeping apps will never run in the background. They'll only work when you run them." So this seems to be three states, sleeping, deep sleeping and disabled, and which of the three is considered frozen? I'm not really sure the definitions of sleeping and deep sleeping are actually different, other than the fact that sleeping apps MIGHT recieved updates and/or send notifications, while deep sleeping apps WON'T. which is a pretty odd distinction.