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