What happens if I plug a power delivery dock to my Mac Mini? I need to use a dock for two displays from my MacBook and Mac Mini. The issue is the constant plugging and unplugging.
I am considering getting the Kensington SD2400T Thunderbolt 3 Docking station for use both with the Mac Mini and the MacBook.

My question is, will this damage the Mac Mini? Does Thunderbolt successfully ignore the power delivery option when not needed.
This will not damage the Mac mini. Thunderbolt chips negotiate the data protocols and the power delivery before delivering any power to any of the two devices. So the mac won't deliver power to the dock and the dock won't deliver any power to the mac.