This shows all the commits to bitcoin core and branches using a visualization tool called Gource.

Here's a video from a year ago with 2009 - 2021, that is an hour long, but helps to demonstrate more clearly what is happening:

1 Hour of Bitcoin Gource from 2009 to 2021

And that Youtube channel has many videos with weekly updates of development progress and more:

BITPAINT Youtube videos https://www.youtube.com/@bitpaint2171/videos