Hm, I'm a KDE user. I just tested what happens when I try to open a folder I don't have access rights for. The standard file browser Dolphin says authentication is required. "Act as administrator." If clicked there comes a warning and I can enter my password. Than it shows the content.

https://i.postimg.cc/VLgkWpy7/image.png

This feature exists since 2022.

https://kde.haraldsitter.eu/posts/kio-admin/

Good! That's exactly what I would like to have happen! I think the error was more like that it didn't have permission to mount the drive. I logged the message at the time, but I don't have access to that computer this week, so I'm going from memory.