I think the idea is there and you’re also able to convey it very much. But I feel like there is missing something to truly call it ambient or to have an ambiance.
While I really like the minimalist approach on the piano, the wind noises and strings are to much right on your face and keep the dissonance to long. My problem here isn’t having a dissonance, but there is no contrast, nothing but the dissonance. If it would have been me, I would have placed the strings farther back intro the mix and make them more subtill, so they would more act like a bad feeling on your back rather than being so notable. Though the wind noises are a nice touch, I would really have loved to hear some additional noises or pads to create a thicker atmosphere, also contrasting the high frequencies of the strings and the clanking of the piano.
Please keep in mind these are just thinks I would point out for making this more fit into my vision of Ambient or Ambiance. That doesn’t mean that your song is bad in any way. Like I said earlier you’re already half way there for a really cool song. So keep it up!
PS. Only now realizing your description. Maybe staying with stock instruments wasn’t the best call for this jam. The goal is focused on sound design and mixing. So having sounds that are working with your vision or creating those to convey it more is key. Also the ambiance part mostly lives from having loads of creative use with plugins. So while I totally with you on limiting yourself maybe this limitation did work against you for this jam ☹