Yesterday we tried to accomplish the 42km panoramic bike trail named the Grand 8 (French jargon for a roller-coaster) starting from Morgins, but my husband’s e-bike battery emptied before reaching the highest hill (that was tough). Still we did 30km and got the very best views of the Dents du Midi. Only when coming back home, I learned that in Les Crosets or Champoussin you can recharge your bike 😅. The Grand 8 should take you 4hours. You can also start this trail from Champéry. It’s a relative easy trail, if you have battery, except for some paths with bigger rocks which make it a bit challenging when biking downhill (thankfully it’s only a short distance like that).
https://goo.gl/maps/xAXUat7HSdkQLQ7FA
https://www.regiondentsdumidi.ch/fr/grand8-e-bike-fp793