The Beginning After the End(2025) _(Saikyou no Ousama, Nidome no Jinsei wa Nani wo Suru?)_
This anime has a lot of potential. It is a sort-of isekai within an isekai. A guy who was a conquering king is killed in his time and realm, and is re-incarnated in a different more fantasy like time and world. He retains his memories of his past life as he has his adult mind's awareness from his birth to his present pre-teen self.
Though his adult mind has tremendously helped him in his focus to understanding and doing magic, there is still much to learn, threats to his family, home, and way of life. On top of these troubles, there people who wish to gain control of him, and barring that they will want him eliminated.
The story and question the MC would like answered begins with: Can he find the peaceful life he had always craved when he sat upon the throne in his old existence?