Yeah, people are recommending amon, but amon is a non Canon spin off, the continuations are Violence Jack, Devilman Lady, then Devilman Saga, however...
The connection between Devilman and Violence Jack isn't fully explained until the last volume due to the mystery of the protagonist and his past, violence jack despite being a continuation can stand on its own, however Devilman Lady relies on the events of the original Devilman manga. Devilman Saga relies on the events of Devilman and Devilman Lady heavily as well.
There is still a connection between violence jack and devilman lady as well though.
Like as a sort of spoiler of what I mean
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Each of the next Devilman series is Satan's attempt at punishing himself and making amends for what he has done in the past by bringing humanity and demon kind back to life from square 1 and restarting all life over, hoping that they can come to live amongst each other peacefully and come together to fight against their common enemy (im not spoiling who). This common enemy though attempts to throw a wrench in that idea though and tries to instigate conflict amongst them though. Akira (though he isn't named Akira every time) usually reincarnates and so does miki and other characters from devilman series and spin offs too
Is there a continuation after this manga?