'''++Patrick Dionne++''' this is difficult since Canon is not DIY friendly and does not publish any of their schematics. Checking the video in your link I’d go with a bad LCD first. It is possible that this is caused by a bad Gamma IC which should be on your LCD PCB assembly.
Would be an easy question answered and a relative easy repair with the availability of schematics etc.. That is why most regular users on here support the [https://repair.org/stand-up|Right to Repair] movement. We are sick and tired of wasting our hard earned money, polluting of our Planet based on the pure greed and paranoia of companies like Canon, Nikon, Apple etc.