Alpe d’Huez with a day trip or 2 to le Deux Alpes, or vice versa.
I like the nature of the trails in le Deux Alpes more than Alpe d’Huez, although there is a lot more than I have explored in Alpe d’Huez. But le Deux Alpes is a bit of a horrible concrete resort, Alpe d’Huez is a nicer place to stay in.
It’s a few years since I have been, and I have drunk beer since, but iirc the blues in le Deux Alpe feel much more natural than Morzine.
Les Arcs is also an option, but the singletrack needs a lot more research to find the suitable routes, and a lot of the bike park feels like a quarried wasteland.