Try out BeardedSpice[0] which handles the media keys
[0] https://github.com/beardedspice/beardedspice || brew install —cask beardedspice
beardedspice might help with your media key issue
https://github.com/beardedspice/beardedspice
or maybe you can force the key assignment with karabiner-elements
I use PocketCasts in conjunction with BeardedSpice [1] to forward media key commands. It works very well!
For me, the main allure of the a desktop app is the support for media keys.
For those interested, there is a Mac app called BeardedSpice that maps the media keys to a variety of websites (Youtube, SoundCloud, BandCamp, etc).