A few suggestions, but 2 hours for an activation of any of them is perhaps ambitious.
Moncreiffe Hill (GM/SS-276) right next to Perth - shortest walk.
Birnam Hill - King’s Seat (GM/SS-221) at Dunkeld. Start at the train station.
Creag Ruadh (GM/CS-092) at the side of the A9 at Drumochter. Cross country and steep flog to the summit.
Meall Mor (GM/CS-109) just south of Inverness.