Is there a built-in data field for this when navigating a course? Basically a sum of current elapsed time + ETE.
Similar is provided for distance (distance + distance remaining = estimated total distance).
Sometimes you are aiming for a distance, which is covered. Sometimes a pace, which is also covered (average pace). Yet sometimes just a total activity time.
Of course, the math can easily be done in your head using what is available, but one less thing to think about is always nice :)
Not that I've found, you can see a list of all available datafields (and their description) here: https://www8.garmin.com/manuals/webhelp/fenix66s6xpro/EN-US/GUID-5176B6E4-F272-4437-BDA7-85B31231CB3E.html
Might be worth a look to see if ConnectIQ might have one from a 3rd party you can download.
Really enjoying the questions you're posting by the way, it's been a nice break from the usual "PulseOX is useless" posts 
Glad you're getting a lot of enjoyment out of setting up and using your watch!
