Except that if you were really good in GA, your first round of opponents will be about as hard as the last round of opponents you face in week five, so pretty much like what everyone else above that said - except the opposite and not really related to a tournament at all. At least they stopped the cross-division nonsense so there's a limit to the GP mismatch that can happen.
Essentially "matchmaking" is now "adjusted" to make sure every match is "fair" or "even". I find both of those terms to be completely subjective and vary widely based on the experiences of the individual making the comment, myself included. CG could remove all mystery by openly stating their algorithm, which would then at least provide some objectivity to it. They would get a lot of feedback and, you never know, might actually end up with something solid in the end.
I am the beneficiary of having several different accounts and can speak to the different impact matchmaking has had on each of those accounts. Spoiler alert, it varies widely - a fact many of the people that post absolute truths about matchmaking are either unable or unwilling to accept. For some, the impact has been negligible, for others it has turned GA from a relaxing walk in the park to a PTSD inducing laugh-fest.
Regardless, the "discussion" has largely devolved into something akin to a religious debate. There is only subjective experience and faith (which is, of course, belief in the absence of proof). There are any number of prior threads on the topic if you want to waste hours of your time and lose a few IQ points during that journey.