Was this the best metal album of 2023? Not by a long shot.
Was it the best Metallica album in 25 years? Absolutely. They tried new things and pulled it off well.
The Grammys have very narrow criteria. Basically you are going to get top 40 radio friendly songs and they choose from that. Looking at the list of nominees, they were the only metal band actually nominated in this category. The rest of the nominees are what people who drive in to “easy listening soft hits” think metal sounds like. 2023 was a pretty weak year for metal anyway.
In my 30s, I’ve come back around to appreciating Metallica. We don’t have many years left of them being around. Enjoy them for the time that we still can. One of these days, soon, they will play Master of Puppets for the last time.