Just as I released my newest feature (Ascender), DCRainmaker just published a comparison of what the feature I was aiming for.
Gist:
Wahoo doesn’t have it - but they do have Strava Live Segments
Garmin ClimbPro and Karoo’s features are similar but Karoo’s is nicer UI wise
Both Karoo and Garmin are affected by the underlying Base Maps they are using / storing in the Head Unit so elevation / slope data granularity are affected. (This is something I’m seeing as well. But not due to the Base map, but to me, it’s more towards the affects of GPS Noise / Barometeric affect due to weather)
Garmin’s ClimbPro also works on their wearables (and I really like this feature for trail running). But there are some others who would like to see improvements. (ref this thread - ClimbPro in mountainous terrain needs some adjustment (screenshots) and improvements with course elevation profile - fēnix 6 series - Wearables - Garmin Forums)