Just for the posterity, you can track indoor rowing in a way. The Vivosmart 4 (as of 6/2021) is pretty smart detecting activity type when telling it you're exercising. Start a new strength training activity on the band, and then start your rowing. Mine detects each stroke accurately as a rep. Rest and start new sets as needed using the interface on the band. When complete, it will upload to Garmin connect, and for me, all but one of the sets had the exercise type set to "Row". I went into Garmin Connect after the fact and updated the activity type and all sets to exercise type of "Indoor Row". I think when you do this, as opposed to "Row"/Strength Training type, the activity summary won't show you individual sets even though the data is still there - it treats "Indoor Rowing" like a bike ride or a run, which is probably how most people view the activity rather than in terms of sets/reps. I updated the strokes/min and distance off my WaterRower screen and it calculated the per 500m pace and calories. So it works well enough for me. I get calories calculated, heart rate tracked, can record pace and distance (I take a photo of my water rower screen) so I can enter those stats into GC later. Not sure what type of rowing machine you have but for WaterRower there are a few ways to get data direct from rower, including the WaterRower Commodule, SmartRow power meter, and the open source PiRowFlo gizmo that you can make yourself for the cost of a cheap RPi and some maker skillz.