Additionally it somehow frustrates when the watch tells me I’m unproductive when I come from an intensive day at the crag ?
You can ignore all that stuff. The algorithms are generic and inaccurate.
How do you folks manage this? Another separate log/diary?
Garmin Connect is good for tracking general volume, but not training stress. Training Peaks or Today’s Plan are better for the latter, and they allow for manual entries in the web app versions.