Just for the record, I am a fan of the Superman movies. I never had an opportunity to read the comic books, but the 1978 Superman film with Christopher Reeve made me a fan. I enjoyed the 2013 Man of Steel, its sequel the 2016 Batman v Superman, and the 2021 Zack Snyder's Justice League. There was also a 2007 animated film, Superman: Doomsday, which only scored 50% on Rotten Tomatoes, but I enjoyed it nevertheless. I also liked the TV series Smallville, although the show went on too long with ten seasons.
Apparently, the comic books reboot their stories once in a while to bring them up to date with modern times. Superman is no longer a 1930's character. The DC animated movies from 2013 to 2021 are based upon a 2011 reboot of the comics whose stories went up to 2015. Then there was another DC comic book reboot in the year 2016.
I was fairly impressed with the 2018 The Death of Superman which has a 92% rating on Rotten Tomatoes. Along with its 2019 sequel, Reign of the Supermen, the movies benefit from a more mature animation style and a more mature plot aimed at adults.
I have mixed feelings about the second film. It tells a pretty good story, but it is definitely darker. There is more violence. Many people get killed. There is some sexual innuendo and sex is mentioned out loud, which is not what I would expect from an animated superhero movie. It also has a frenetic story. It is a busy film, which can be both good and bad.
Together these two films make for pretty good entertainment. All three animated films are available on HBO Max.