Not obviously. I usually just-copy stuff across into folders, into a live session of the app I am currently working on. This is in File Explorer, not unreal.
I make sure I have the same folder path, creating new subfolders in the target app if necessary. I can then copy the bottom-level folder, with textures, .uasset files therein, etc into the new app.
Works for me. I just tested in 5.3.2.
If I open the material and it points to things I forgot to copy, like the missing MPC subfolder I forgot to copy-over, it will bork THAT thing, even if I don’t save it. If I then do copy the missing item(s), anything else, will open OK.
EDIT: and the thing that I broke-broke, I fixed by closing the app as the asset was locked and could not be copied-over. Then copied, then reopened, worked.
A FWIW, I do migrate stuff between projects, usually from the marketplace project directly into whatever; I don’t want to have to hunt for stuff at the file level, the migate works out the dependencies. But that aside and/or once that is complete, at the file-leve, just-copying .uasset files (folders) works, for me at least.