Curious if this was resolved for you. A lot of what you are dealing with sounds like my truck. I can get temps up to 180+, but only after a good 1/2 hour, or a hill climb at 60mph or so.
I think your tach must be set too low. I can't imagine getting the turbo to spin much at all at 2000 rpm, and I can hear it in your video.
My truck will do 60, and 65, but it does not like to go 70. The RPMs I see are just about 100 too high as compared to the charts you can get from Ashcroft, so I know that my tach is set a bit high, and I can compensate as I look at it. I know that the fueling is good, I can't see that there is anything wrong with the throttle cable, but my EGTs are very slow to react. It takes 10 minutes to drop from 650 to 450 when at idle. And on a good hill at 50-60mph it will take over a minute to get to 950+. I have never seen it go over 1250, even on a hill, 5th gear, 55mph, floored.