Precisely, why people have a hard time getting superman. In short, i was expecting this answer. Sorry about being a smart ass. People largely don't know who he is based on. They know what he has become. He is basically a combo of jesus, hercules and essentially a tree/sun god, like you said. Superman is based on tarzan, john carter, doc savage, strongmen, mythical heroes(hercules) and gladiators(the phantom and spartacus). See, the only reason hercules part of his inspiration still lives is cause of all star. Even that would have gone away. Anyways, viability of this combination is upto you.Also, clark kent is based on a harold lloyd's comedy character.
Why is he the saviour/messiah now? Well, it's basically a means to make sense of the portrayal of the character giving morality lessons to kids during comics code days even now.Essentially, this kinda portrayal where superman gives kids guidance.
It was a portrayal that started later on with comics code influence and not before. But now, it's to keep that portrayal alive with adult audience, since comics code isn't there. Let me elaborate, superman talks to you like a kid and gives adivices/speeches. They needed to explain that, so they made him space jesus .
Ofcourse, You could argue about the whole "el" thing. But, siegel and shuster's character was "jor L". He even had a prototype before the daybute of superman, in an old comic with same name and by same creators. in federal men, where jor L battles Nira-Q.
https://dc.fandom.com/wiki/Jor-L_(Federal_Men)
Either way, i think the messiah thing was largely the company's direction with character. Not the creators.why do i think that? jor eL has no equivalence in judeo-Christian stories,as far as i know. The only connection is kal el. It doesn't appear in the first issues of superman and action comics at all.
These are the two origins done by siegel and shuster. They didn't much believe in origin stories. They wanted the current stories to be what matters. Anyways, kal el is a name given later on (might have been editorially enforced). Either way, I have no solid proof of it. Its a hypothetical. I could be very wrong.
the only counter evidence to mine, is the names of adoptive parents which was john and mary. Regardless of this i do believe, the above portrayal of superman as space jesus is something to explain his behaviour, currently.
Clark's alien heritage though acknowledged was largely a means to explain his abilities. Which was essentially equivalent to a strongman with steel like body.
Furthermore, batman is based on superman's vigilantism and success . Its never acknowledged. Zorro or grey ghost takes all the credits.See, what frank miller did was take batman back to his portrayal to a more adult oriented style that existed before comics code. With superman, that transition back never happened. They instead opted to use contrived reasonings to explain the s being a symbol of hope in krypton, the strongman suit (similar to the phantom) being a fashion choice of Kryptonians, glasses disguise... Etc. And the above talking to adults like kids,as saviour/ jesus like figure.This is just my interpretation of the history of the character. It's completely flawed.