Steam Deck not detected as audio device over bluetooth

When I pair my phone to my Steam Deck over bluetooth, I’m able to send audio from the phone to the Steam Deck and listen to that while I play games.

However, when I pair the Steam Deck with my laptop (Framework running up-to-date Manjaro with KDE Plasma) it shows an icon of a monitor or all-in-one. When connected I do not have any additional audio devices listed. I can pair bluetooth earbuds and they work as expected.

I don’t know much about Bluetooth but I believe the the term I’m looking for is Bluetooth Profiles. The Steam Deck supports a profile that allows it to play sound (A2DP?) from other devices.

How do I make the Steam Deck available as an audio output device over Bluetooth? (If it helps it is also running a fork of Arch and using KDE Plasma as its desktop environment.)