The fastest way to get more Google reviews is to ask every guest, at the moment they're happiest, with the fewest possible steps between asking and the review form. Here's what actually moves the number.
Review gating is showing different guests a different path based on how happy they seem, usually by sending happy guests to Google and unhappy guests somewhere private instead. Google prohibits it, and hotels have lost reviews or had profiles suspended over it.
NFC cards work with a tap and no camera app, which makes them faster at a handled touchpoint like checkout or a check-in queue. QR codes work on every phone without needing an NFC chip, which makes them the more reliable choice for something fixed in place, like a table or a bar.