After reading and seeing too many e-book reader devices I decided to go with a tip of a friend and bought a BOOX Tab Mini C [link].
System: this runs an Android 11 operating system. It seems it was shipped without the typical Google stuff on it but that was fixed quickly.
Apps: this was shipped with some Chinese setup (via Aliexpress) but that can be changed to English. After installing Google Play and F-Droid via an apk, it seems that most relevant applications, such as to access files elsewhere, or e-book reading software, were easily added.
Memory: while the memory is only 64 GB, it seems to force me to keep focused on what I actually wanted it for: text reading. There are other devices that are better suited to put in memory extensions, run a full Linux, and watch videos. This is exclusively for text reading and for that it is enough.
Screen: oh, it is so perfect. It works at night, and, in super full sunshine. I love the pastel type colors also for comic book reading, and the touch screen/pen work with perfection. When reading newspaper online, the whole overview of a newspaper pages is not exactly as clear or detaild as the resolution of this device does have its limits. But as it is it is a great e-book reader.
Battery: very long lasting.
Remove bloatware / install apps: set USB debugging to enabled on the tablet, connect tablet to computer, install ADB if you did not already [link], there use command line command adb shell, then remove packages with pm uninstall -k –user 0 (package name). You can put Google Play Store on there or F-Droid. One might then use an app called “package names” to check what’s on the tablet.