Good to hear we isolated the disconnection issues to the 2m cable. Unfortunately I don't have a good recommendation for 2m cable. I've used AKiTiO, ASUS, and Razer without issues but people's experience have been different. You may have to try until there's a good one. You can also go with the Apple .8m option if that's long enough.
I would prefer a 2m cable of some sort. Another option is to buy a long displayport cable. Do you know what the limit of a displayport cable length is?
I apologize for the 200 questions.
The lower bandwidth is due to either an external SSD (attached to Gaming Box) running concurrently or a firmware that limits throughput. You can flash the H2D firmware that allow full Thunderbolt 3 enclosure throughput which is 2,6XX/2,2XX for Nvidia cards.
AIB are definitely better in the noise dept. My Asus Strix 2070 OC is basically silent.