With your strength training background you surely do fall outside of the normal range for most mountain athletes. I’ve seen this before. I’ve had strong guys needing to carry 90ld pack to get this ME training effect. These athletes tend to be more aerobically limited and surely not strength limited. Work to move your AeT up. I suggest finding the AeT NOT with nose breathing. See the recent forum post about nose breathing. Use the HR drift test to find AeT.