Photo?
Is it a place where you have to have grass?
Why put grass or artificial grass where it does not want to be?
Is it sunny..what about a groundcover suited to the slope and sun availability? This way you are not fighting what wants to be. If you fill in your location ..folks inthe know can perhaps give you suggestions.
I agree 100 percent with Betty and ask for referrals and get expert advice about the possible construction remedies.
Agree a deck maybe $$ but in the long run, if it solves your problem and provides you with useful space..it will " payback "
