In actuality, the watch face does not do any of the actual tracking of steps or heartrate. The watch tracks all that information inside its operating system. The watch face only polls the API on the watch itself and from there it displays the information that it receives.
It is just my guess, but I think the general settingss you do in watch interface affects only the stock (preinstalled) faces. Facer is a separate app that displays faces and to gather the data, does access the sensors on its own. That would also explain, why the values may not exactly match the built in health apps.
There is a way how to find out, if you are willing to experiment and give it few days. If you could not find such, I can make you 4 watchfaces (maybe not so fancy, but for comparison even the base should work), identical but for the features: one basic, one with HR, other with step counter and one with both. After a day of regular use you could compare the remaining battery charge.
There is an issue with this new camo face
The numbers up top that are supposed to switch back and forth between date and HR/steps wig out for lack of a better term, constantly changing and or adding up and even go off the side of the screen.
Synced back to your original for now
Just for grins and giggles, I synced your Camo Green face that @tom.itssos was having issues with. I used my test Fossil Carlyle gen 5 and it was “wigging out” just like Tom was saying and showing in his video. WearOS is very picky on expressions which is why I use a WearOS watch exclusively for testing. If a watch face is going to screw up, it’ll happen on WearOS for sure.