Hello,
In Revit you need to open the folder that I point in your image. You need to pass Revit the path to that folder, not to what is inside!
So fo example, if you have a path that is Autodesk/Revit Server 2021/Projects/FOLDER.rvt
Just pass that path to the Revit API. I know it is weird because it is a folder and not a Revit file!!
But this is how it works.

EDIT: Sorry I forgot to mention, that you will need to transform the path to a Revit Server Path!
So if my path is:
\\revit-london\Autodesk$\Revit Server 2021\Projects\2054 SingleHouseProject\Model1.rvt
I need to transform it to:
RSN://REVIT-LONDON.zzz.s/Autodesk$/Revit Server 2021/Projects/2054 SingleHouseProject/Model1.rvt
Note that I also changed this / to this \