Inserting a piece of paper between the spacebar and the button seems to have worked for me. I folded the paper over the end of a credit card and used the credit card to both pry the spacebar upwards slightly and simultaneously push the paper in. I also have a fairly recent laptop: MS-16K3 with a GeForce GTX 1070. Bought about March 2018.
The guide is excellent - detailed and thorough. However, I managed to pull my display apart, separating the glass from the OLED part, rather than pulling the whole display out. It wasn’t obvious until it was in pieces. Not really a fault of this guide. But beware and don’t make the same mistake.