That looks like a classical guitar in the video which may have different dimensions to your instrument. Have you tried to play this on your own guitar?
3 or 4? I’d say you should work on fretting hand dexterity and strength regardless of the scale length of your guitar.
But of course, if GAS hits, that’s another matter.
Also, for the song in the video: Guitar Challenges (Songs) - Is There Anybody Out There? (Pink Floyd)