The HRM-RUN also has it (source: It's what I use) and the Garmin Running Dynamics Pod also provides it.
Personally I've never found any actionable data from these things though - read up on what DC Rainmaker thinks as well, he says the stats are interesting but there's nothing you can do/change to effect them easily.
I have been using RD capable HRMs and later RD Pod for almost 10 years and have yet to find a use for the data, but somehow can't stop using the RD Pod because I might find a use for the data at some time in the future. Pure FOMD. Fear of missing data.
What are you trying to achieve? The most accurate HR data? Then a strap is still a great idea - I have a HRM-RUN and I got it for accurate HR data. Wrist is OK, but not super accurate.
If you think you will get good, actionable data from oscillation, cadence and ground contact time and aren't too worried about super accurate HR data, then a Running Dynamics Pod would suffice.
To me though it makes more sense to spend the money on a HRM-RUN (or PRO if you need its features) for the more accurate HR data PLUS the RD data.
But again - it comes down to what you're hoping to learn/achieve with the data.
Forget about that data. You will not get it, even with using an RD Pod or an HRM strap, because Garmin introduced a bug in Firmware 21.00 that results in garbage data being recorded from RD Pod / HRM Strap. Garmin is either not able to fix this bug, or they don't care anymore. A fix was promised a long time ago, but never materialized. The result is that the running data from the RD Pod or an HRM strap and all of the derived metrics are not usable.
There are lots more posts in the beta forum for the Fenix 6.
You can see from the graphs posted that the RD Pod / HRM running data is severely broken, and this has been going on for over two years now. Garmin promised a fix but failed to deliver so often that I have given up hope that this bug will ever be fixed.
As I recall it, it was (is) a bug when you use a RD capable heart rate strap AND an RD pod, with stride length and some of the other metrics. I use a HRM-Run and RD Pod and foot, pod and have valid RD data, but this bug has not been solved for all configurations.
