Heart Rate Data for Manual Activity

Showing the HR from the all-day data would make little sense, since most of the metrics (like Training Effect, Training Load, VO₂max, HRV, Respiratory Rate, LTHR, Stamina, etc.) is being processed in the real time by the watch, and cannot be extracted from the all-day HR data (sampled in 2 minutes intervals) anyway, hence it would be rather misleading. If you really need to see your HR during the activity, check out the all-day HR graph on the Daily Summary. You can select the section and zoom it:

I don't care that metrics my watch doesn't even have can't be extracted from the heart rate data. I do not have training effect or training load. What I am looking for is a chart of my heart rate and other measured info during the activity. If the watch is only measuring my heart rate every few minutes that's news to me, but I suppose the previous fitness tracker I had was doing it differently or was able to somehow still measure my heart rate during a period of time.

If you're saying the heart rate is misleading during a period of time then why isn't the chart that you posted misleading since they don't tell you that they only measure it occasionally? In addition that chart does not zoom in to a specific time (in fact it doesn't even show the times) on my app so it's not really as useful to me. It's hard to see. From your screenshot it looks like it also doesn't for you, so I'm a bit confused by that.

All-day HR is recorded each 2 minutes (average values over 2 minute periods sampled each 15s). A timed activity is recorded with the sampling rate up to 1 second (may be little bit less in case of the "smart recording").

CM said:

In addition that chart does not zoom in to a specific time

As you can see on the screenshot, it does - just select the concerned time interval with your mouse (click & drag) and the graph zooms into the selection

CM said:

in fact it doesn't even show the time

Again, it does - see the screenshot. Additionally, you get detailed data, including the time and HR value wherever you point the mouse cursor. Time scale is also under the graph - see the gray dots (there is 18 under the second dot, since this is a zoomed section, not the entire 24hr graph)

So, only on the computer not the app. Great. I see a point in time on the hover, but not a time I can set that I want to view or a distinct period of time. It's definitely not what I want or what I'm looking for, but if you say the watch isn't built with that capability I guess it is what it is. It's just a little disappointing because it was something I was used to having with other fitness trackers.  Just disappointed because I thought it was a common feature in trackers from past experience with others. Thanks for the option, though. I don't use the computer as much to view my data and didn't realize there was at least a little bit that I can see if I zoom in a lot on the computer.