I am in utter disbelief after reading about your opinion, did you check whether this is the visual novel you're actually referring to!?
It is so baffling seeing that someone has basically the polar opposite opinion about this visual novel than me.
This piece of media has, in my opinion, one of the best character writing of anything that I've ever read. And seeing you boil down their personalities to two or three words makes me feel like the whole point of every single one of them has gone over your head.
These characters act anything but stereotypical, and even the ones that do seem archetype-ish, like Carl, make a point by portraying the deeper parts of their reality.
And now that I mention Carl, let us take him as an example. He is one of the "weakest" characters personality-wise, but it is easy to see that such is the point; Carl has been consumed by monotony and depression to the point where his personality as a whole has been watered down to the core, which resulted in an "erasure" of his confidence and sense of self-worth. This premise is typical, yes, but in a relatable, realistic way, not stereotypical. He's not a caricature, yet even he thinks of himself that way. That's where his richness as a character lies.
And the animosity amongst the friend group is such a refreshing dynamic that it couldn't work any better; It feels awful seeing them deal with each other, and that's genius writing. The years of tension and basically forced friendship (because of social circumstances) is felt through every argument and interaction. You feel how everyone knows each other so well, that they've reached a point that they have nothing nice left to say, and communicating that much every time is pretty much a feat. The conversations, the interactions, feel realistic and backed up by backstories, and that just gives so much to the immersion of this visual novel.
I could write paragraph after paragraph about what each character entails, but that would make things too long.
With Echo you're reminded that you're not reading a simpleton visual novel about a bunch of sweethearts in a creepy place. The tension and the insanity within Echo and the friend group sells the horror beautifully and realistically.
The unorthodox way that Echo has of telling its story is key to absorbing the reader into the experience. It's not disappointing; it's novel. And you came here with unfair expectations when you wanted a chewed-up novel without ever having to squint between the lines.
Of course I don't think Echo is perfect, but i greatly appreciate each of the aspects that make it unique as a novel. I'd love to see more writers dare to take up such an experimental atmosphere and message like what Howly did here.