Why would you take sedan to mountains?
I mean even Vitz and Prius can go if you really want to take them. Grande too can as it's higher.
But
You're buying specially for mountains then don't get Grande.
A higher ground clearance crossover/SUV will be better.
If you want real offroading..get a used PRADO.
IF want new, then Sportage AWD is slightly better than Grande. But minor difference.
Sportage too is not meant for mountains but can do mild rough tracks. Grande too can do mild rough tracks.