Ramp rate and ACWR are already the result of calculated metrics (from all activities) and you can’t filter out per activity. Basically there’s no Ramp Rate number per activity because Ramp Rate is the result of the Fitness numbers for all activities.
You need to redo the complete math from load, which is an activity specific metric. Just like you had to recalculate Fitness/Fatigue/Form from Load to get them for running activities alone.