I think your songwriting and your voice is great. But you should put more emphasis on the production. Your great songwriting will shine through so you shouldn't be shy to let the instruments take over the song at times. Here's a song that sounds like something you would possibly go for, but note the production of the song.
Foxygen - San Francisco (Official Video) - YouTube
I'm not entirely sure what your influences are but you should listen to how some of the songs you listen to are produced. Listen to how they mix and EQ the instruments. If you really want to get more vintage, keep the sound way more in frequency. Keep most of the instruments in the midrange and let out some of the air out in the upper frequencies. Doing this can be hard to achieve because you can end up with a muddy mix. Let your ears do the work though.
I still think even without going more "lo-fi" your songs can get better if you just focus more on being a producer than being
a songwriter/vocalist.