Cannot Setup cardio fitness on Apple Watch 7

fiery jack, thank you for your reply. As I mentioned in my question above, I have followed all of the setup procedures I can find here and elsewhere online. In the link you provided, in step 3: "Tap Set Up", there is no setup button to tap.

Thanks for those suggestions. I will try those for my next outdoor workout, which will likely be tomorrow (I have reset fitness calibration several times already, tho). With the watch in airplane mode, should I take my phone with me on the walk, leave it at home, or does it matter (since it's in airplane mode)? Just wondering if there is any data that the phone tracks separately from the watch like GPS, or something.

Just wanted to revisit this here. I tried your suggestions above with no luck. After contacting Apple support, I was able to actually speak with someone on the engineering team. After analyzing my workout data, the issue turned out to be that my Apple watch, for some inexplicable reason, would just randomly stop tracking my heart rate for several minutes at a time. Sometimes it would be just a few minutes into the workout, sometimes maybe 15 or 20 minutes in, but there was always a gap (I'm reasonably certain my heart was in fact beating during those gaps). So I'm going to see about getting a new device.