Hey, thank you so much for giving such detailed feedback. Let's see how I can address it:
Indeed, the green spot on the map is there to help you. I couldn't test it much with users to figure out if I should keep it or not.
The digging needs to be improved indeed. You have to find it by digging quite a lot at some points. It was indeed not your fault, it is more of imprecision in the system.
Yes, the last level has a wrong X spot to confuse the player.
The camera switch was an attempt at giving other options. Some testers found it nice and preferred to use it, but some others, like you, thought it was not helping it at all.