If it does work, it will only work at 4K 60Hz.
unless....
5K 60Hz requires connecting a Blackmagic eGPU or Sonnet eGPU Breakaway Puck RX 5550 XT/5700 or an eGPU that supports DSC (AMD 5000 or 6000 series). See egpu.io website about connecting eGPUs to Thunderbolt 2 Macs.
Another option for 5K 60Hz is to use a Thunderbolt 3/4 add-in card to convert two DisplayPorts from the Mac Pro to one Thunderbolt 3 connection. This method might not work or it may require additional work.