Yes that fear of failure and criticism is what's causing me to speculate on what I'm doing. The thing that keeps bringing me back is I find my idea for this story so damn interesting. I was reading the Wiki article on deus ex machina the other day and suspect that may have been the catalyst.
Then write for your enjoyment only. Don't share until you believe it's as good as it'll ever be, if you have to at all. Most early writing never sees the light of day, anyway.
Symbolically, I love to write fantasy. I can cloak real truths under a seemingly pulpy story. 'Real' literature has a harder time of that - everyone knows there's a deeper meaning involved.
I write science fiction because it's the genre I enjoy reading and thinking about. I value scientific plausibility so I do spend a fair amount of time researching things to convince myself that my fictional world is at least semi-realistic. For example my work in progress takes place on a tidally locked planet orbiting an M class red dwarf. There is considerable debate in the exoplanet community about the potential habitability of such worlds. In fact there seems to be a rising consensus that they are probably not habitable. However, I did run into a paper published a few years ago where the authors did some computer simulations of atmospheric dynamics suggesting that the question may be more complex than it at first appears. I latched on to the results of that paper and modeled my fictional planet after it. The scenario worked for my story and it is at least consistent with some views of reality so even if it eventually proves to be wrong, I'm satisfied that I've done my homework. In the process I've learned a lot about exoplanets and red dwarfs in particular. Nothing wrong with that!
Google "Asimov On Science fiction." "Science fiction is an existential metaphor, that allows us to tell stories about the human condition."