Did typing su prompt you to type a password?

Had similar issue, but was simply downvoted. I used KDE Partition Manager and set the mount point to /run/media/deck/. Then at the top, choose the option to read by Label (or something like that). Other option is to open Dolphin as root (open terminal, login as root with su, then type dolphin), and make a folder in /run/media/ that’s the same name as your microSD card. Then set THAT as the mount point.

Does it use a mod loader? If so, change that mod’s priority to be the highest (i.e. put it at the top of the list).