I can add the disk as you usually do thru the steam settings UI, but it doesnt create the files and I cant manually create and add a steam library folder to the disk. is there some security setting I am missing? something I am doing wrong? I have the drives mnt and formatted in ext4.
It’s possibly a permissions issue.
If it’s not already, try mounting the drive to a directory within your home directory.
Ext4, like all unix/linux filesystems works with permissions.
By default if nothing else has been done with the disk but format and mount .. it is likely owned by root.
You may create a directory and take ownership of that for example and put everything there.
Or you could use certain options in /etc/fstab to mount it a certain way.
And so on.