Scenic drive from Fussen to St Moritz area

we are driving from Fussen to Lake Como, planning to stop in the St Mortiz area overnight to get a break from the drive and tour the are briefly the next morning. Can you recommend the more scenc drive? Is it along 27 or is it better to go down A13 and cut across from Thusis to St Moritz? Which is the easier drive? Thank you.

Fussen - Reutte - Leermoos - Nassereith - Landeck - Scuol - St. Moritz. No Swiss motorway sticker needed for this route.