I have a 2017 and listen to Sirius plugged in through the cigarette lighter outlet in the glovebox. I got an extra holder for my small house Sirius radio and the plug online. The sound can be heard tuning to Aux at the bottom of the menu that has FM in it - it only becomes active when you have something plugged into that outlet. Or you could listen to jazz through Sirius or another app on your phone.

 

I am by no means going to provide a definitive answer but I did study this stuff in college many years ago so here goes. First of all two stations who broadcast on same frequency must be separated by a specific distance, determined by the FCC, which depends on the amount of kilowatts (power) they are broadcasting. In your case I'm guessing that you are located somewhere between the two station towers. For some reason the design of you antenna in your Subaru, probably located in the rear window, is configured in a way that favors the FWIW station. The CX-5 antenna obviously prefers 80s and 90s pop rock. Unfortunately there is not much you can do about it other than find a new station, buy another Outback or move closer to the smooth jazz area. On the plus side you do live in the beautiful San Antonio area. I know this isn't going to fix your problem but hopefully you have a better understanding of the issue.