Hi Travis_Lloyd,
Thank you for reaching Microsoft Community and ap[ologies for the inconvenience this has caused you.
Just to make sure though: the issue with the speakers detected as microphone is already resolved suddenly after plugging the old headset where the Headphones (Surface Dock 2 Audio) suddenly pops up and now the speakers are detected as audio output device. However, in Windows Media Player, you have to do a restart first every time you change the output from internal speakers to external speakers and vice versa in order for the change to take effect, correct?
Does this behavior also happen outside the Windows Media Player like while you are watching video or playing music through a web browser then change the output from internal to external speakers by selecting the Sound icon on the Taskbar then change the select output device?
Which Surface pro 9 configuration do you have? Intel or 5G?
Whenever you change the output device between external and internal speakers, kindly try to check in Device Manager if a driver is banged out or getting an error before you do a restart to have the change in output take effect. If a driver is banged out, please take note of the name and share it to us then try to click Action and select Scan for hardware changes. See if it applies the change in output device instead of doing a restart.
For the actual manual concern, I'm sorry but no, we do not have a user manual available for our Surface devices and accessories.
Let me know how it goes.
Kind regards,
Marrion