Fit issues seem to be gradually falling into place and your fitness for cycling will improve with more miles also. Be aware that as your fitness improves, your best position on the bike may well change also. My experience is that the best position is a moving target and small changes over time, as you adapt, can make a substantial difference. Then there is having the right gearing for the terrain you ride and level of fitness. Even tour pros change gearing for different events. Finally, technique can help or hinder. https://www.youtube.com/watch?v=HRFNKhNhhJQ Some tips in the link for climbing. I am especially taken with how smooth the narrator is while climbing and try to copy that for myself.