How do I get the middle point of faces to show in edit mode? I always see it in videos, but have no idea why I don't have it and how to search for this function
The dot in the middle of faces only shows when you are in face select mode - that is, the mode whereby you can select entire faces rather than just edges or individual vertices.
I seem to recall it used to be enabled by default, so perhaps it was disabled by default in an update at some point. Either way, you can re-enable this behaviour in the Viewport Overlays menu, accessed from the drop-down button next to the symbol with the two circles shown in this screenshot:
Note that the required option only appears in edit mode.