Check out Beinn a’ Ghlo. What I did was hike up the staircase from hell that you can see from the A9 onto Carn Liath, bike on back job. After that can descend to the bealach, and then do the second munro on the ridge – go back the way you came and fork off left down the wee path at the bealach again. It’s a fun descent, a bit broken up in places.
Carn a’ Chlamain also supposed to be good as mentioned. I actually did that on my gravel bike on the landy track (quite the experience), but meaning to check out the singletrack path too. Looks nadgery. In any case it’s an easier one to get up with a decent amount pushing or even riding, compared to carrying.
The fun parts of Beinn Dearg behind Blair Atholl are fun near the top, but short lived as there is a big land rover track most of the way up and down so a bit boring.
If you can stretch your travel to closer to 1h30 north, Sgor Gaoith is a total blast. It is in Glen Feshie roughly level with Kingussie, so you’d have to drive over Drmochter first. It’s easy to hikeabike or even ride up a lot of it, and the middle descent down is unreal.
Beinn Glas and Lawers are both great rides, the latter is pretty tech and steep from the top but the path from the saddle to the carpark is great fun and largely flowy with some tight tricky bits. Similarly the Loch Earn Ben Vorlich is good.
Ben Vrackie is also good, quite a quick out and back from Pitlochry itself, don’t even need to start the car.