ACER PREDATOR IPS 4K 60HZ XB271HK 27" EN FRANCE

Hello, It's an Acer Predator XB271HK screen monitor (4K 60hz IPS panel G-Sync) paid for 800 euros 3 years ago. I was very happy with it until the day it started to bug. It works but the screen becomes dark, darkens every second (interval of 1 second between the normal screen / the screen bug) So I opened it once to clean it, being careful, I take great care of my equipment. (no physical damage and the screen is in excellent condition) despite this, the problem persists. Sold with power cable and foot for repair or part. If someone knows about it and finds a solution, I am also interested. Cordially.