Clicking through a bunch of them, I was horrified by what kind of permissions they want on the phone. Read/write everything, full network access, prevent the phone from sleeping and other things that have nothing to do with just editing a text.
It looks like to just open+edit+save a text file, an app needs no permissions at all. Probably because Android allows every app the right to read/write files when initiated via a user file picker dialog. Notepad by Braden Farmer does it this way. Unfortunately it has a cumbersome workflow of keeping the text files in private storage until you "export" them. If it would always "export" instead of saving it to private storage, that would be perfect.
Another perfect way to handle reading and writing would be to use Scoped Storage. Then the user could decide which folder the app can access. I have not found any text editors that do this yet.
I found some very old text editors still on the play store that only want the "Read and write everything in shared storage" permission. Bad enough, but even those seem to not be an option. I know Coastline from previous Android versions, but it fails to write files in mysterious ways on Android 11. Jota has too many buttons on the screen and even managed to crash in a desktop like fashion, showing me an OS dialog, saying the app is unresponsive and asking if I want to wait or force kill it.
Unfortunately, there is no way to search for permission on the play store. So I don't know if there is a friendly, simple text editor for Android out there. If you know one, let me know! I will keep this page updated (and announce it on Twitter) if anything comes up.
I got dozens of suggestions for text editors after I published this. Although it looks like most people don't know how to check permissions of an app in the first place. So most submissions were along the lines of "Check out this editor, it is very simple! Needs nothing but file access!" but the app actually requested every permission under the sun.
But there was one that really does not require excessive permissions! And it is ...drumroll...
Simple Text Editor by Maxistar.
It's kind of ironic that it has this name, which is exactly what I asked for in the title of this post. For some reason, it is nowhere to be found when I search for "text editor" in Android. Even though it has over 500K downloads. Maybe it is a localization thing? Android only showing software that was translated to your local language?
Anyhow, turns out this editor is actually nice. The only thing it lacks is scrolling inertia. So scrolling to the end of a long file is cumbersome. And it would be cool if it used the new scoped storage permission instead of carte blanche on everything in your shared storage.
If my fellow readers have more suggestions, let me know. I will keep updating this page and tweet about it.