You can use DP output from your video card to a MST Hub that can connect up to 3 or 4 Displays at one time if you are going to be using 2K Monitors.
Many AMD Professional GPU cards supports 4 -6 Displays.
AS AN EXAMPLE ONLY this AMD Radeon Pro W6800 supports 6 Displays:
With 2 DP 1.4 MST Hubs that can connect 4 Displays you will have your 8 Displays. This GPU Card should have no issues with 2K@60hz to connect 8 Displays. I might be wrong but just looking at the Resolution chart in the image above.
But AMD Professional GPU cards are generally quite expensive. There are many Consumer GPU cards that supports 4 Displays that may be less expensive.
EDIT: Reread you original post and you mentioned about Daisy chaining several Displays. Found this Dell Support on how to do that: https://www.dell.com/support/kbdoc/en-us/000128707/how-to-daisy-chain-multiple-monitors-using-displa...
The above article is for DP version 1.2 which has less bandwidth than DP version 1.4