Application list might be missing r or obsolete

Did you purchase the NAS new or used?  I ask because you appear to have things done to it that can only be accomplished via SSH, yet you claim you don't know how to use SSH.  If you purchased it used, the previous owner made changes to it that are now interfering with the new OS because the base Debian version was updated.  Updating does not necesarily destroy those (depends on how they were done).  A factory default does, which is why it has been suggested.  The problems you are having are not data related, they are OS or App related.  Restarting those with a clean slate is the fastest way to overcome that, and possibly the only way since you do not seem to know everything that has been done to the NAS.

You admit you know little about the NAS, but hold the belief that your opinion is better than the advise of someone who is very knowlegable.  If you persist with that position, there is nobody here who can (or likely will even continue to try) to help you.