Google Shared Drive sync to my PC

Apparently you cannot add shared folders as actual folders to "my drive" anymore by some web UI element. It's only possible to create shortcuts (.gshortcut) for now. Unfortunately, these shortcuts do not allow the folders to be synced by "backup and sync".

However, there's a somewhat hidden key combo that establishes the "old" way. When you select the shared folder in "shared with me", you can press "Shift-Z" (btw, this is listed in key combos available from the gear icon top right), and then select where to put the shared folder inside "my drive". "backup and sync" will now pickup this as a real folder.

Okay, I misunderstood at first, but if I'm comprehending your question correctly, all you need to do is right-click or access the context menu of the file or directory that was shared to you from browser, and select "Add to My Drive". The file will be added to a folder that also shows up in your explorer.exe, and it should still sync (not a redundant copy), assuming Backup & Sync is running.

EDIT: After seeing some more comments, I went digging through the Google Drive Help community and managed to find this post, I hope this might provide more details or answers for those with the questions about this particular problem. Here's a screen capture for retention: