I see. You gave plex access to all of your data. I just had not looked at the mounts inside the container when you do it that way.
The "advantage" of giving plex access to all your data is it makes it so you don't have to bother with understanding volume mapping.😉 Actually, I do that myself, and I understand volume mapping very well.
However, instead of giving it access to /mnt as you have done, I give it /mnt/user. In other words, I am giving it all my user shares, whereas you are giving it all your disks and all your user shares. Plex is unlikely to break anything like that, but in general I wouldn't give anything direct access to my disks, mainly because you should never mix disks and user shares when managing files.
Don't change it though or plex won't be able to find the media it has already scanned.