I really like the bass arp and lead you used for this! I think your vocal arrangement is already solid for this, staying a little monotone seems to work, which I think is just because I remember listening to 80's/90's show ads with electronic music and monotone vocals (and as synthwave, that is definitely an accessible reference point).

Some people forget the subtle pitch bend on synths, I love hearing that so thank you (RC-80 by chance?). I think that sidechaining your vocals separately from everything else would be worth trying, because the sidechain is a bit strong and if you still wanted a hard sidechain, I would at least leave some room for the vocals (I think your vocals sound good, I wouldn't be afraid to show em off :) ). When your lead comes in at 50s, I wonder how gradually bringing down a low pass filter would sound to signal the end and at the same time make more room for the lead, might be worth trying.

I think this is a successful POC, good job!