My -Samsung Mobile phone S9+ is listed ad connected device, but show no Folders and Files.
Tried this but in vain:
"Some Samsung MTP devices will work better if you set Preferences / Miscellaneous / Advanced: mtp_enable = False, so that Opus falls back on the system’s MTP support instead of its own."
Make sure you unlock your phone (put your pin in) after connecting it to the computer. Sometimes you also have to select the type of connection (file transfer, rather than picture transfer or charging).
I see my phone in the folder tree. Click it and the I see the Phone drive in the lister. Clicking the drive and it's a dead link.
But clicking the down Arrow left of the phone folder, show the drive. Clicking the drive in folder tree, the content lists in the lister.