Gauges are different from countdown timers or progress rings. They are a special element that is not meant for real-time progress updates.
However, the ‘dot’ will eventually update itself at random intervals as widgets and Watch Complications are refreshed.
Widgets and Watch Complications have their own ‘update budget’ that is controlled by WatchOS or iOS for the sake of battery life.
Thus, consider them as cosmetic only and not as a progress indicator.