Do you know an app or any other mean to save at least the list of installed apps and their settings?
Via adb shell pm.. and fdroidcl you can script this if you also source alot from Fdroid. Can give you a guide. But for configs… when will Seedvault integration land?
The problem is that for /e/ OS preinstalled apps, I have no solution
If you want to use the default Gallery App to access the sdcard, you can follow @AnotherElk suggestion and use:
adb shell "pm path com.android.gallery3d"
adb pull /system/product/priv-app/Gallery2/Gallery2.apk
adb shell "pm uninstall --user 0 com.android.gallery3d"
adb push Gallery2.apk /sdcard
… and install via File Browser. Simplemobiletools Gallery is an alternative.
And thanks for checking it out, I too would like to use the external sdcard with a default install 