Can't get Apple Watch to show up as SOURCE for Cardio Fitness - SOLVED!

The set up: iPhone 11Pro, new 1st-time apple watch 6

Got it in October and did all set ups. Did home workouts using the app. Tried Apple Fitness+ workouts as well. So my phone's been collecting data into Health already and the watch is sending info to it. BUT it never shows up as a source in Cardio Fitness and obviously cannot add it (there's no button to add).

Finally decided to do the whole go for a walk for 20 min calibration. I even turned my iPhone's Apple Maps ON and left it on in the background, just in case. iPhone screen off and in pocket.

1st walk, more than 20 min using the Outdoor Walk in Workouts. It didn't register my Heart rate because my watch was still set to Always On (ON). I'm assuming due to this being ON, it was able to gather enough data to start calculating. So when I got home, I turned this OFF. I also spent more time searching through all these posts to make sure I don't miss something. I realize that on iPhone>Workout>Power Saving Mode was on. I turn it OFF.

Next day 2nd walk: 34 mins, iPhone maps on again just in case, iPhone in pocket.

In the Fitness app summary (for this workout) I can see heart rate measurements throughout the whole workout. (I made sure my watch was right up against my wrist so it could. So I hoped it would be a good 2nd & final workout and start showing Cardio data. Nope.

I search again for something new. I did read one guy on here mentioned that in the iPhone Health app>Walking + Running Distance>Data Sources & Access he found multiple instances of his watch. I check mine. Sure enough for some reason, my only watch is listed twice as 2 separate sources. As well as old phones of the past that were collecting steps data for years. I decide to eliminate ALL sources except the connected watch and the current iPhone 11Pro. First I rename my 'connected' watch to "Watch 6" so I can differentiate it. I know which watch is not connected because when I clicked one, it said this watch is not currently paired. Huh! So now I delete the older watch listing. I restart the iPhone.

Now as an additional test, I'm also doing this with my wife's iPhone XS and her new watch6 I gave her last week. She ALSO was not seeing Cardio Data, and neither of us had attempted the 2x walk workout outside calibration. We were only doing in-home workouts. Her watch was ALSO listed twice as a source??? as well as older iPhones. I delete their data and again only leave the data and source: the current iPhone and currently connected apple watch 6.

By the way, I did NOT Reset Fitness Calibration Data. I wanted to eliminate as many possibilities first. You can find this in iPhone>Watch>Privacy. I also did not put my iPhone in airplane mode. Like I said, just in case, my iPhone was running apple maps in the background and in my pocket.

Same day, 6 hours later, 3rd walk: 20 min. Halfway through I realize my watch isn't on tight enough and probably can't get a good heart rate measurement. I tighten it. I get home, check the summary and "Chart Unavailable". Oh, well. Make sure that watch is on tight from the beginning!

I check Cardio Fitness>Data Sources & Access and BOOM! There it is! Apple Watch 6.

The only thing different from what everyone else is doing (based on the same suggestions) is those previous sources. And I had to dig and look for them. I'd seen them before as having contributed data for years (steps and steps) and I always figured:keep them. But why 2 instances of my same watch? What if the iOS is "confused" with so many sources? I dunno. So I deleted.

And maybe I was lucky.

We won't know until other people try the same thing.

Let's see if this solution works for more people.

Good luck everyone.