changing inputs

Hey everyone. I have 3 lg 27gn800 monitors. And got an hp omen 27k 144hz 4k monitor from a friend and when I plugged it in it works fine but when I switch inputs from display port 1.4 to hdmi 2.0 or 2.1. all of my monitors turn off and on. And my hp omen takes a like 15 seconds to change inputs...