That is a solution, but not an ideal one for many (most?). One of the great innovations of the smartphone is that I have all 3 devices in one small form factor, so I don't need to carry/travel with the bulk of many.

I actually went full old-school and got an portable cd-player.

This has the side effect of me listening to music more intentionally and not wasting time selecting tracks and skipping around. Listening to a full album is great, something I rarely did before. And physically owning music feels great.

Sure, it is less practical for traveling but it mostly sits on my desk to help me get through work. And CD's having a fixed run length helps me to take breaks so my tinnitus does not get worse.

That's fair. I miss MP3 players and even feature phones - all of them could be operated without looking at them!

Alas, ever since Apple showed it's Courage™ by ditching the audio jack, Bluetooth headphones became ubiquitous (doubly so thanks to AirPods and alternatives). They're nice and all, but they also have mikes, so you want to use them for calling and voice messaging too, and then you can also put notifications on them, ... with Bluetooth device switching being what it is, this complements and reinforces smartphone's role as single device for everything.

EDIT: I wonder if it's possible to have some kind of mixer wearable that would accept wireless audio streams (both in "music" and "headset" modes) from multiple devices, mix them together, and route to a single set of wireless headphones. That would solve a lot of the issues I have with wireless audio in practice.