If Jor-El and Lara had identical twins, do we get two indistinguishable Supermen? I don't think so.
Let's call the twins Clark and Calvin. They have the same genes (identical twins) and both are raised by the Kents. They might even decide to share the Superman role- posing as one hero. But they are unique individuals none-the less. Clark might marry Lois, while Calvin might marry Lana (or even Jimmy) and find Lois uninteresting as a potential mate.
To me the question is whether you consider the OP question closer to "What if Clark (the specific twin) wasn't raised by the Kents"? or to "What if Calvin (someone genetically identical to Clark) wasn't raised by the Kents"?.
Pre-Crisis most Imaginary Stories seemed to be taking the same person (the Earth-One Superman) and putting him in different scenarios. At the same time in-continuity stories (Earth-One, Earth-Two, Earth-Three) seemed more like identical twins. The characters were all the first-born genetic sons of their universe's "Jor-El and Lara", named "Kal" and raised by a couple named Kent but were distinctly different people.
I would pretty much from a meta-physical standpoint picture the Earth-One Pre-Crisis Superman as having a different "soul" than the Earth-Two Pre-Crisis Superman. In the omniversal Heaven they both exist separately. But I picture only a single "soul" that existed as the Earth-One Superman, "the Superman Luthor killed in the original Death of Superman", "Clark (Batman) Kent" who took over the Superman role from Lex Luthor, a hero called Nova, and Hyperman of Canada in a sort of simutaneous version of reincarnation.
So the specific Clark/Kal from a current Superman comic wouldn't become more similar to Homelander if Doctor Manhattan removed the Kents from history, but there could easily be a parallel world where a different Kal became Homelander-ish because he wasn't raised by Jonathan and Martha Kent.