If this case had a jack that worked reliably, I'd totally buy it. It's just that every other adapter I've used has somehow had occasional hiccups where the phone plays via speakers instead.
I built one into a dock in my car that charged the phone and delivered audio to my car radio.
They earned their reputation when new phones came packaged with the adapter for the first few generations (circa iPhone 7/8?) after the 3.5 mm jack was removed.
Or in my case I've got an audio receiver with flaky Bluetooth. Guess it's "my fault" for not replacing it with an Apple TV, better yet Homepods.
Reminds me of when Android phones used to do the same with analog audio jacks.