Hey! Best advice for the issues here is to add "fluff" to your writing. Just create a few meaningless scenarios to add extra time getting to know the characters. This can be a view of them interacting with each other, or it can be a moment of awkward conversation with the strangers you just met. Whatever gives enough exposition to give the reader an idea of their identities.
If you'd like a good example of this, try out an old VN called Katawa Shoujo, and pay attention to how each character is introduced. There's different introduction styles for each character: Emi (legless battering ram), Hanako (establish eye contact then panic), Rin (immediately ask if you have a "downstairs disability"), Lily (ladylike grace), and Kenji (legally blind Dale Gribble).
Don't despair just because your first iteration isn't getting the results. Everything in life is an opportunity to learn. I can't wait to see where you go from here!