Hello, thank you for reaching out to Microsoft Q&A.
Make sure your audio output isn’t switching between devices. If you have multiple audio devices, Windows may switch to a different output device, which can reduce the volume. Temporarily remove the other audio output devices, then check whether the volume remains stable. If you’re still having issues,
1
Try running the audio troubleshooter -
Click Start > Settings > System > Troubleshoot > Other troubleshooters > Audio > Click Run.
Once the troubleshooter is finished running, restart your computer and test the volume.
2
Reinstall Audio drivers once -
Go to Device Manager.
Expand the arrow next to Sound, Video, and game controllers.
Right-click your default audio driver, Realtek (R), select Uninstall device, select the 'Attempt to delete the driver software for this device' checkbox, and then click Uninstall.
Once uninstalled, restart your computer and test the volume.
Let me know if you still need more help.