Do not have "add button" in APPS

Hi Bennor, thanks for your fast reply!
I have read all this carefully and several times. However, I did not understand how to bypass the defective Accept button. When and where the commands has to be entered. As already written, I have tried different variants.

Now I have found in another thread a variant that works for me.

I have downgraded the firmware, the button with the commands activated. (in an older version, the accept button works) and manually installed the apps “WD Cracks 1.2” and “PhpMyAdmin”. (binaries from http://fox-exe.ru/WDMyCloud/WDMyCloud-Gen2/Apps/)
After a firmware update, the add button is gone again, but the installed apps remains.

Do I understand correctly that with this hack I have to rely on the selection in the file archive of fox_exe?
There is no chance for me as a user to officially update my app PhpMyAdmin?
Thanks