Exportation of heart rate data from Apple Health or Apple Fitness (NOTE*: regarding to these two apps, not iCloud*)

Hello! I am curious as to how I can efficiently export heart rate data for given exercise activities from the Apple interface related to the activity, which is either Apple Health or Apple Fitness. I have been able to do the "Export All Health Data" from the Apple Health app, but have trouble accessing the XML files from Apple Files on my iPhone. Any attempts to download, share, ore self-email the data have also been unsuccessful. What I am specifically targeting to access is the heart rate data collected during exercise, along with the amount of calories burned (energy expenditure). Any tips on how to approach this? Thanks!

-Cooper N.

p.s. - I could not find Apple Health or Apple Fitness in the topics category, so I defaulted with iCloud