Poor sound quality on iPhone (all generations) when compared to iPad, MacBook, Apple TV via bluetooth headphones

STRAIGHT TO THE POINT 

This isn't a subjective opinion, it’s a fact; when wirelessly streaming music using bluetooth headphones, iPhone suffers in sound quality when compared to almost any other Apple device. When listening to Apple Music on my Apple TV 4K, late 2013 MacBook Pro with Retina display, and my 1st gen iPad w/ Retina display, the sound quality is vastly improved with a more expansive sound stage and higher fidelity throughout the frequency range. The differences are more noticeable with full/medium sized wireless headphones, and some high end bluetooth in-earphones. 

Has anyone else noticed this? Is there a fix? Is there a setting in iOS 12 that can remedy this problem? These findings aren't anything new; I've noticed this for years with the past several generations of iPhones. 

ADDITIONAL INFO

Music Sources: Apple Music, Pandora, Spotify, Apple Lossless, FLAC

Wifi: Gigabit Broadband with wifi speeds of 600 mbps

Settings: EQ is turned off on my iPhone as well as my other iDevices. I have the highest bitrate selected for audio quality