Hey sorry, I never saw this reply. I now have notify turned on in here 😁. Adding Google Drive File Stream to my Alfred search scope works (defaults to looking like a mounted drive and has path of /Volumes/GoogleDrive) and I see file and folder results. Because the files are streamed when opened and not really there by default, I added a "File Search > No Previews In" for the path to prevent potential unnecessary Internet traffic for previews as I use Alfred to search.
When I drag a file from GDFS into the Metadata tool, it works as expected... the tool freezes a minute while I see the GDFS menu icon "spinning" indicating it's downloading the file for use (a similar experience to a slow network file server).