This is a known limitation of the Snapdragon X Elite laptops … while you can make audio output via the speakers work through some devicetree hacking, there is no speaker protection in the stack yet which means you can easily blow up your onboard speakers by accidentially pushing the volume above 100%
Instructions on how to make the speakers work anyway (if you are brave enough) can be found in the megathread about the X Elite images:
I personally decided to better wait and simply live with headphones for the time being on my XPS until the stack is fully working …