It also seems to be working for me although LR now seems to be hung importing the last 600 of 27K images. Do you think it's just processing in the background? I don't see anything other than "Import files at their current location" msg and hung status bar.
I too just recently installed Google File Stream. I'm still experimenting with it and don't know a lot about it. However, I just took a couple of quick raw files that don't mean anything, really. I uploaded them to the Google Drive and allowed time for them to synchronize. Then I imported them to Lightroom Classic using the Add option and everything functioned normally as far as I can tell. I was able to immediately begin editing the images with no apparent issues. The key apparently is to allow the images to synchronize before trying to import them to Lightroom.