I tried this and my 70km trail run course copied directly to NewFiles shifted from Garmin Connect reported 300m elev gain to more realistic 1100m (still differs around 100m from "raw" gpx file), and it even shows the climbs somewhat correctly when previewing the course on watch (FR945).
It still has some issues and it is a little weird that it includes a lot of flat ground before the actual climb as part of the climb, when the climb is short and steep, but that I can live with....
And now as we are getting that PacePro this comes even more important! If they want us to have proper courses they should not f.. up the elevation in the courses.
I fixed GPX elevations with GPS Visualiser and then small convert with GPSies that Garmin connect accept it as activity (as I have bad experiences doing this with some import, they usually just are bad). Then with the activity I can disable elevation corrections and see proper data, but if I select "Save as Course", the course will have elevations "corrected" and I've not found a way to disable that. Sucks.
this only happens to my if i import a course via garmin connect. the elevation data is ridiculous. if i import the same course via the komoot connect iq app, the original elevation data that also feeds into climbpro is correct. that's why i am using this workaround. something with gamins algorithm is broken?! i am also seeing these spikes.
i also started a discussion - including pictures here:
Well, commented there on my take on the problem :) https://www.dcrainmaker.com/2020/05/garmin-launches-strava-komoot-route-sync-works-on-devices-a-decade-old.html#comment-3568123