dietpi-drive_managercould need some time if it tries to contact a network share which is not available anymore. It tries until it reaches the timeout.
But you said it appears
within every dietpi tool
only via SSH
only in your LAN (because at your brothers house it’s working fast)
I would rule out a hardware problem, because it’s not always slow, only with special conditions.
Sounds like a problem with your network to me, and not with DietPi itself
For example when you use dietpi-drive_manager do you see some lines after you hit enter (like:
dietpi-drive_manager [ INFO ] DietPi-Drive_Manager | Detecting drives, please wait...
and then it stucks or does it need minutes to show anything?
It looks like my dietpi still has a /mnt/MyBook which was the drive i was syncing from still listed, but its not listed in the dietpi-Drive_manager im wondering if its trying to reconnect to that and cant. how do i remove it?