I think it looks fine and you’re probably too hard on yourself (as most artists tend to be) in regard to how something looks and the things that might be “wrong” if characters were drawn like this and in a VN it would be just fine on quality and style. I would be happy with art that looked like this.
I think the main issue comes of course as a solo dev on a project like a VN is it will be more than just characters. Backgrounds, CG’s, characters and details along with programming, coding, writing, etc by yourself. And it would make the most sense to make a smaller in scope project to practice how you want to tackle the approach rather then jumping into (to be fair like a lot of devs do) a larger project.
Something like @Roops The Breakfast Chub - Roops’ Submission - Gain Jam / Fat Fortnight 7/2019 - Weight Gaming is a smaller in scale tight little VN and it’s one of my favorites shorter games. It obviously was a lot of work and done by more than one person on a short time schedule (cause it’s a Jam game obviously.) Someone with less experience on the art side will obviously have a bit of time eaten up by that and maybe trying out a smaller scale format will give you the best idea if this is how you want to do something going forward.
Because quality wise your fine in my opinion and other factors of solo dev while trying to learn/perfect your own artist might influence you more than how people feel about the art (which like I said is good you’re being too hard on yourself).