Calibrating Apple Watch if I don’t walk a consistent direction or speed

They say to walk on a flat surface for 20’ using the Apple Watch as one normally would to calibrate it correctly. However, I am training my dog, and need to change directions, going the other way, then changing back on a fairly frequent basis (usually less than 1 minute each direction). The other problem is I need to stop and pick up poop on occasion, so I am not walking at a consistent pace.

Can the Apple Watch calibrate correctly under these circumstances? If not, what if I do walk consistently in 1 direction for 20’ on one occasion. Will the watch then be correctly calibrated and record accurate information when I walk while training my dog as described above? (To complicate matters, I actually have 2 dogs, one off leash, and need to make potty pick-ups for both.)

My experience has been that I do not get credit for the full amount of time I walk, based on the Workout App, if set on Outdoor walk. Sometimes the watch does not register my heart rate, so I get no credit for that part of the workout.

Looking forward to help and advice.