I think the Shinigami life was intended to be some kind of purgatory
I’ve been rewatching Deathnote after many years and I know that the writer said that in the Deathnote universe there is no life after death.. But I believe the writer originally had other plans.
First because of the rule that a deathnote user can neither go to heaven or hell. Why have that if there is no heaven or hell?
Secondly I believe the shinigami life is some kind of purgatory due to the fact that they die if they kill someone to save someone they love.
It’s like that if you find love again in your life and not be selfish you are finally free again.
Also if the theory that Shinigami’s are previous deathnote holders was correct it would reinforce this.
Anyways this is my headcanon🤷