I've purchased a CS-Pro USB DAC adapter (https://www.aliexpress.com/item/1005004763520790.html) as all of the small basic local ones I tried (including Ugreen and Samsung's own adapters, and all Bluetooth devices) have a low-level analogue background hiss noticeable while listening at very low levels (2-3% volume for night time listening). The sound on this higher spec dongle (Cirrus CS46L41 chip, S/N 125+dB) is lovely for the price, and there's no hiss, but I've encountered a really strange problem which only seems to occur on the Galaxy A54-5G.
The A54 (and only the A54) does not recognise the three-button events (Play/Pause, Vol+ and Vol-) from my headset's inline cable when using this CS-Pro adapter. This is at the device level, it won't even change volume on the homescreen using the inline buttons, so it's not app related. And it happens with multiple Android-spec 3.5mm wired headsets (including Samsung's own) so it's not the headset itself. Running a key-button-event monitor shows nothing at all is reaching the OS when any of the three buttons are pressed.
The three buttons all work fine with this dongle on my other USB-C household devices, such as an older Galaxy A40, Galaxy A70 and an Asus tablet, so thinking my phone was faulty I popped into the local O2 phone dealership to see how this dongle worked with more recent phones. We tested the basic Vol+/Vol- buttons on the sales assistant's own Oppo phone and that was fine. We also tried every live Samsung phone on the store's display - an A14-5G, A34-5G, Z-Fold5, Z-Flip5, S23, S23+, S23-Ultra - and they all worked perfectly EXCEPT for their A54-5G.
So basically three-button headset controls with this dongle work fine on every phone in Samsung's range except for the A54. More recent stock firmware updates (currently running the 1st October patch update) have not helped.
I assumed when I got my A54 that connecting my 3.5mm headsets would just be a case of getting a little adapter and it would work just as it's always worked for the past 20 years. Not so much apparently, thanks Samsung.
Any thoughts on how I can progress with this issue?