Microsoft have updated the firmware of the Surface Earbuds adding a new audio codec option. With version 3.0.6 of the firmware you can turn off or off the aptX codec and with it off the earbuds will use the SBC codec. This reduces the audio quality but increases battery life.
Details from Microsoft:
Enables an option within the Surface Audio app that allows the ability to turn on or off using the aptX codec. When turned off, Surface Earbuds will use the SBC codec.