Thanks for playing!
Level 6 does get pretty difficult (and I agree it’s a little unbalanced), but there are ways to lose cobb even if you get seen or sensed. If you run into darkness while he sees you, try staying completely still - he won’t be able to hear you. (There is still a chance he might investigate the area randomly) This doesn’t work if he has smell, you’re right about that - but smell is proximity based, so your best bet is to keep track of cobb’s position on the map and not get detected in the first place.