dropbox install problems centos 7.6

Operating System: CentOS7

Probelm 1: Dropbox is not allowing me to select /mnt/raid5 to sync my files to because the mnt directory is not showing in the Dropbox gui when I try to find the directory.

What have I done: I have installed and uninstalled Dropbox sucessfully twice now using Flatpack as per instructions and have let the files sync for over a week each time.  This clearly isn't working.

Desired result: Sync Dropbox to /mnt/raid5 directory and there can be peace across the land.

As you can see the image in the left shows /mnt directory but the image on the right does not show the /mnt directory as an option.  Solution have a developer add the /mnt directory which is a standanrd Unix location to the GUI.  Problem solved.  Or tell me how I can download my files to my local machine /mnt/raid5.  I am aware I am unable to download more then 10,000 files at a time.  

What I tried to do was create a sym link from /home/Dropbox to /mnt/raid5 as a work around.  

It looks like the sync is partially working as you can see some of the files in /mnt/raid5 however the files are taking space and being saved on /home/Dropbox not /mnt/raid5 and now /home is completely full as you can see in the image below yet raid5 has only 1% used, clearly stating the files are being saved on /home/Dropbox even though the symlink is working as per UNIX standards.

Problem 2:

Dropbox "start up automatically" setting is not saving settings to "start automatically".  I select the box, press supply, but if I reboot my server the check mark for "start up automatically" is removed.

Problem 3:

There is no ETA of how long the sync will take place in the Dropbox toolbar.