On Samsung S7, I use the native recording app and sometimes DU Recorder to record my games. Each has its perks. For the timer, I use a simple app called floating speedrun timer. It can get in the way of your playing, so make sure its in a good spot before you start recording.

On Amazon Kindle, I use SmartPixel to record, upload to Facebook, download, and add a timer in a video editing software called ShotCut.

If you have a different way of recording and timing, please share!

For iOS I just upload it to my YouTube channel