Southern Peru, Bolivia and Chile would be a good option, but it’s all so varied, and it depends what priorities you have. For cultural experiences, it’s very hard to beat Bolivia, and the scenery is amazing to, with some fantastic walking and riding opportunities. Linked with some time in Southern Peru, it would be great. The only thing is that riding/guiding is only developing- i was there over 10 years ago, and there was some great stuff to be had doing the Camino de los Muertos, but it’s essentially a gravel road. there are probably many more options though.
If adventure is the priority, Chile and Argentina are worth a look. It will be winter then, but at lower altitudes, riding is always possible, and the Chileans are especially into mountain biking. Also, there should be snow in July! Valle Nevado in Chile, Las Lenas (Mendoza) and Cerro Catedral or Chapelco (Rio Negro/Patagonia) in Argentina are all small, but well specced resorts, but with limitless back country off piste- with a guide! Bariloche in northern Patagonia is a great base for both summer and winter adventures.