SUMMARY
User might want to move a file using hot corners, from say the dolphin window, into another window within the desktop grid into another program.

This goes hand in hand with moving a File into another activity, or detaching dolphin tab into another workspace/activity.

A new file manager instance/window might be used by a user from within another activity/workspace as a way of separating the context.

A "open new window" each time is a workaround of sorts, but it gets weird when it is combines with remembering the last session, while the current dolphin session is still in place, producing 2 tabs when launching.

OBSERVED RESULT
None of the described behaviors are working as user intended, visually user is able to move a file into desktop grid, visually take a queue into moving it to a specific window in a different workspace.
Hold off the mouse button and change to a new workspace, the context menu for move,copy,link shows up in all workspaces, user changes to workspace in which he had places the mouse over, click the button and it copies a file back into the same folder within dolphin.



EXPECTED RESULT
User is able to move/copy/link/place files from within grid view.
User is able to detach dolphin into another workspace and/or activity.
Dolphin shouldn't try to restore it is old session, when launching new windows, when other instances of dolphin are running.
[Perhaps some users will disagree on whether this should be opt-in or opt-out]:
User is able to create a new window in a new workspace/activity, otherwise all new folders opened from plasmashell should recognize which activity/workspace we are part of.



SOFTWARE/OS VERSIONS
Linux/KDE Plasma: Arch 
KDE Plasma Version: 5.20.5
KDE Frameworks Version: 5.78.0
Qt Version: 5.15.2


I will link all of those related issues in every single one of them and link them together, as it requires some degree of cooperation between those 3 modules(dolphin, plasmashell, kwin).