I am planning to buy a Turner DHR mainly for freeride. – Jumps, drops, technical trails, bridges, etc…-

Despite the lack of two rings, would anyone see any disadvantages?

In what scenario would the HighLine outperform the DHR?

Would the Highline be the more active under extreme braking? Where you have to completely stop the bike, then start over… - Not very often you have to stop in a DH course…

Why there are no DHRs in the RedBull Rampage? I have never seen a DHR in a North Shore movie/video…?

You should be posting on the Turner or the Downhill forum for answers.
There should be someone there to answer your questions.
:D