This is nonsense the guy spent something like £10 on 2m lengths of cat 8 as his existing cables were not long enough. There were no expectations!
He changed the cheap ethernet cables and noticed an improvement in sound in his system. If you frequent the computer audiophile forums there are reports from loads of people who have done the same with cheap cables. There are also plenty of people who have experimented with cheap switches , ethernet isolators and reported differences, even swapping Ethernet ports on a switch.....
This is all you need to know to understand that these things DO make a difference in some systems.
Then it comes down to individual choices and value but you won't really know unless you try!
I bet none of the "lol"brigade have tried any of these things and done any critical listening, because classical network theory tells them it can't make any difference. If they did they probably wouldn't hear anything anyway because of expectation bias