I tried to connect my 27" Apple 4K Thunderbolt display to my Voyager laptop and initially it didn't work.
I ended up buying two Samsung 28" displays and because of the configuration of my ports, they had different resolutions. Following the Voyager manual, I was able to go in to BIOS and change the Thunderbolt 3 port to Display Only, so with one connected to HDMI to HDMI and the other connected with a T3 to HDMI adapter, I was able to get both to display 3840 x 2160.
I had purchased a Thunderbolt 3 to Thunderbolt 3 adapter to fit the mini cable on the Apple (StarTech TBT3TBTADAP) from StarTech.com before going in to BIOS and it didn't work. Once getting the Samsungs to work through the BIOS change, I tried the Apple again, and it worked. The resolution is 2560 x 1440 and is crisp and beautiful.
Unfortunately, I can't remember if I had downloaded something from Apple or elsewhere (I did read the StarTech directions and followed them) when I tried before and it didn't work. If you have a Thunderbolt port on your laptop or PC and you go into BIOS and change the port to Display Only, and it still doesn't work, you may need the Startech adapter and additional downloads.
You may have to restart your computer after connecting.
Now they all work at once, but at different resolutions - not a big deal in my situation.
Hope this helps.