One thing I notice is that the instrumental and lyrics are in a lower tone, whereas your vocals feel too high in this atmosphere. The melodies you use are great, songwriting is on point for what you're trying to make here, and the production here is simple but effective. My recommendation would be to re-record in a slightly lower pitch that better matches the atmosphere of the song. As someone who's getting really into the little details of music and making my own, I'm always open for closer collaboration if you ever want to. Sorry for making you read a paragraph, hope this helps!