The biggest problem you have is with the backing track, there’s not much you can do with it to improve the overall mix.
The backing track volume definitely needs to be a lot louder to balance out the overall mix of sounds, the problem is if you do increase the backing track volume, then your sax sound is clashing with the singers volume. The focus is on the singers and they have already been balanced with the band tracks.
The only way round it is not to play when they are singing. It’s not your fault, your sax mike recording is ok, just a bad choice of track unfortunately.
Saying all that uploading recordings is more about everyone hearing how you play the sax and thats great, well done. You sound very good on the sax.