Assuming for a second that McVay will try to run the same type of offense...yes, Gabriel might be an option. However, I believe that his concussion history is on par with that of Cooks (and Cooks is a significantly better WR).
As an alternative, I wonder what the Bengals' thoughts are on John Ross and might they be open to a trade (thinking 2021 4th rounder). He has his own fair share of injuries and I doubt that the team will exercise its 5th year option on him. I doubt that the Rams would exercise it either so it'd be just a one-year rental. I think a healthy John Ross (whatever that means) would be more intriguing to McVay than a healthy Taylor Gabriel (whatever that means). I'm just not sure which would cost more for 2020.