Whoa this one was a real surprise - so glad you finished this one. Make more! The only thing I would wish to hear in this one is you bringing back some of your guitar playing - that always adds the icing on the cake haha
Mixing/mastering wise - more of a preference but I usually try to dip the center channel low-mid EQ a bit on strings/choirs/brass, so lead voices like the synth at the beginning or harp later on blend in more and sound less like it's standing separately from the rest of the mix. But more of a preference and didn't really affect my enjoyment of the song.