OneUI 4.x (not sure about earlier versions) has a very nice screen recorder that allows you to record both system sounds as well as mic.
It also allows a selfie video feature that records your face (or anything you want) using the front camera.
With taps and touches enabled, you can also use annotations during recording.
Additionally, if you install NiceShot Good Lock module, you can customise the settings even further to your liking.
Do remember that not all phones are supported at the moment.
Hope you learnt something!
