All of what you said is 100% correct.
That said, his coaching record, and even his GM record, is indisputably remarkable (ignoring the comments from idiots and mouthbreathers). And so it is a bit strange, unexpected, and even sad that he is likely not going to be coaching in the NFL this coming season. And, yes if he is indeed done with coaching, it does suck as a fan that there will be a media narrative that he didn't match Shula's artificial wins record, and an inane media narrative that he "didn't win anything without Brady". He should be a first ballot Hall of Famer when he is finally eligible, and should likewise be inducted into the Pats Hall of Fame when first eligible. And those same stale narratives will get repeated at that time as well. At the very least, they are a bit irritating.
I'm sure he's disappointed that things ended the way they did. He certainly had hoped to stay in New England for at least another couple of seasons, and that didn't happen. He's probably rightfully a bit peeved that his track record didn't earn him a longer leash to move on from Mac Jones. But, at the same time, he'll land on his feet, and it's not like he needs the money. It is what it is.