The song composition is really good. I like the song. The timing and performances are spot on. The mix balance is good. Really well done there. Now for what might improve the mix, since that is what you are asking for.
I know the drums are programmed, but the snare could use more thwack and less pop.
The vocals are where I would focus most for improvement. The levels are all over the place. If I were mixing this, I would just go through and ride the fader on the vocals. Pull down the louder parts, for example "now" at 1:27. Also, it seems there is either a de-esser on the vocals, or a lot of compression that is turning "s" into "th", for example at around 0:40 "thomething tho good". Just pull back on the compression and use a fader ride to even out the levels and restore some of your esses.
At around 2:48, when things get really quiet, you can really hear a hiss. Sometimes that comes from over compression, raising the noise floor. Could be another track that isn't muted during the quiet part. I'd search that out.
Overall, a really good effort. Thanks for sharing