I received the sabrent adapter and also the q800t, didn't work with the end of Januari nvidia drivers I had installed but after updating the nvidia drivers to 466.27 (end of April) it worked immediately on 8k 60Hz.
Haven't done a lot of testing yet, it doesn't look like GSync works over the...
I'm planning on doing a very similar setup, q800t with the same usb-c adapter on my 2080 super laptop so thanks for confirming it works. I'm on a samsung odyssey G9 (49" ultrawide) right now, I only game very occasionally and I do a lot of software development work so I expect/hope 8K would be...