The best kept secret is the one no one knows ! Spoiler: until vol 16 Even the MC does not remember his true identity, there was barely a hint in one of the short stories !
Kumo Desu ga Nani Ka - later chapters after she becomes a goddess, the moment she unleased her power, is the moment that life will cease to exist in the world. Saiki Kusuo - too overpowered for the world
The best I can think of is Han Li in The Record of a Mortal's Journey to Immortality. Basically from the beginning to the end.
Thanks for the recommendations, already read most of them though, so only remaining ones are Monster Paradise and otherworldy evil monarch