ClimbPro for Navigation?

Yes, climbpro works for courses that are generated by the watch "on the fly", meaning when you use the watch to navigate to a saved location, or "return to start", etc.

Climbpro on the Fenix 6 Pro models does not require the course to be generated by a phone/computer, the watch is able to generate the climbpro data itself using its own internal data.

The Climbpro datafield setting is for what you want the little bit of data that gets overlaid on the Climbpro datascreen to be. The default is vertical speed (the rate at which you are going up or down), but you can change it to be whatever you want - time of day, calories, distance to destination, etc etc.... many dozens of choices, pick whichever one you'd like.

Thank you very much! 

Have tried it by myself, it works for Navigation 'on the fly', amazing! 

I guess ClimPro screen should automatically appear on ascent beginning, but not, I need manually change data screens.

One more side question :) Auto Climb? What is it? How to use it? What are Run Screen and Climb Screen as settings for Auto Climb? Also what is Mode Switch?

Have tried to turn on Auto Climb, just noted on some points screen was inverted and nothing else.

Please help to understand! Thank you! 

I don't use Auto Climb, but here is my understanding of how it works:

It is supposed to detect when you are climbing (by using your current rate of ascent, which you can manually adjust that threshold if you want), and when it does, it switches to whatever datascreen you define as your "Climb Screen". For example, maybe you have a datascreen set up that has data more specific to climbing, versus a datascreen that's primarily for when it's flat or downhill. When you are not climbing, it either goes back to the screen it was on before ("current screen") or a different screen of your choosing.

It has 3 usage settings: "Off", "when not navigating", or "Always". The "when not navigating" option is probably best for most people, because otherwise it might be working in tandem with ClimbPro if you have a course loaded.

You can set the screen colors to invert when a climb is detected (in case it wasn't already obvious that you're going uphill, I guess).

And finally, the "mode switch" adjusts how quickly the watch will switch between those modes... the "sensitivity", I guess. So "Fast" might mean it enters "climb" mode on even the shortest little hill, while "Slow" would mean you'd have to be climbing for longer before it switches to "Climb" mode.

Thank you for detailed explanation! Have tried it based on your recommendations. It seems "Climb Screen" and "Run Screen" are working exactly as you explained. Initially I was confused cos both settings were set to the "Current Screen" and nothing changed except color inversion. I have found Auto Climb function somehow not properly finished cos it will be more smart to have as "Climb Screen" an additional screen which is not in the set of your regular screens for activity, but this special Climb Screen activates only if climb is detected. As with current Auto Climb implementation I should manually set climb related screen which is not useful for flat activity and I just need to do an additional click to scroll it when I need others screens.

Have not tried yet "Mode switch" and Always / When Not Navigating ... going to experiment later. 

Thank you one more time for you effort to explain these functions.