Why can I only mount external disk via CLI? ["SOLVED"]

Disks mounted via your user are mounted differently than when you sudo or with root. The driver needs FUSE support to allow you to mount it via your user.

You can find more info here: https://wiki.archlinux.org/title/NTFS-3G#Allowing_user_to_mount

thats probably part par of the course for the arch experience

id check if Udisks is installed and running.

I have no idea what that GUI thing is you're using to do the mount, but I note that the CLI and the GUI are not using the same mountpoint. Is it possibly the case that the directory /mnt/storage2 exists but /run/media/void/2TB does not?

If you're using GNOME or a derivative, you should probably be using gio mount to do the same mounting as the file manager would. Then again, you say that the file manager isn't working, so gio mount probably won't work either.

I admit I had no idea about the guts of this - and maybe still don't - but the user who suggested looking at udisks is probably right. It's always been there in the background as long as I remember (Mint/Cinnamon, many years), and has hooks into something I mounted with gio after the last reboot.

Another search term that might help is "gvfs", or GNOME virtual file system, which I've definitely poked around with before.

Importantly, Nautilus and gio don't need sudo because they call into what's already running. They (or the subsystem) automatically create the mount point directory (and remove it on unmount). If the directory already exists, they use the "append a 1" technique you experienced, presumably so they don't clobber or hide something that might be important.