i enjoy understanding the physiology, but the data take the joy out of the activity for me. it seems like most people use these devices for motivation. ive never really needed that. i know when ive had a hard workout, and i know my pace and HR pretty accurately. when i go out for a 10 mile run, i typically can pin the time within a minute.
as far as rowing/erg is concerned, i agree that it is a "harder" workout. it'd be akin to running with a weight vest or swimming in maple syrup. but as you state, that also depends on your pace and resistance. i'd like to hear from someone who does a lot of both running and rowing what their impression is. most people don't row for 2 hours, but many run for 2 hrs....
I do both.
Rowing is harder for me, but I've run competitively since 6th grade.
Rowing is much more physical in the short term, as it takes you to threshold quickly, and no amount of proper technique changes that.
Long runs are very physical of course, pounding your hips and knees. You don't brutalize your body with a rower, but you CAN get hurt on one. The low back especially.
Your running technique and the way your parents assembled your body matters with regard to cardiac strain while running. Tweeking your running form makes a big difference, same with swimming. The better your form the better you swim.
Even perfect rowing form hurts. It just sucks. There's simply nothing you can do about it.
Screw "the data," which do nothing tangible in terms of guiding your training. There is nothing more beneficial than listening to your body and crushing it when it needs to be crushed, and going easy when you need to go easy.
I have a Whoop strap and spent some time obsessing over it but it never changed anything. My son uses it now during cross country. I like the HR graph bc it's fun to see, but make no mistake it changes nothing. The sleep fxn on Whoop is BS.
There's probably something to watching your HRV and using that as a data point which can change based off any number of things.
No matter how smart you think you are, you can't outsmart human physiology number one, and even if you could it doesn't matter bc your genetics play a huge role in elevating or lowering your ceiling.
Edit - Please don't run with a weight vest. There are few worse things for your back and pelvis. Just don't do it.