Report the Bluetooth problem at the Subaru service. When my wife drives back from work, our '15 Forester pairs with my phone on the kitchen table as soon as my wife stops the car in front of the house. Easily 15 feet and there's walls and the car's chassis between us.
This is pretty hilarious by the way because if the phone just about pairs and she turns the car off, iPhone keeps playing the music, just switching to the internal speaker. We have a running joke about her "walk-in theme playing".
It is a problem with the 2015+ WRX regular head units and is regularly reported as an issue. The 2015+ Navigation units, plus a few years prior, do not have the issue.
This is pretty hilarious by the way because if the phone just about pairs and she turns the car off, iPhone keeps playing the music, just switching to the internal speaker. We have a running joke about her "walk-in theme playing".