A D will harm you far more than a W.
Had you taken Chemistry before?
AP Chem is one of the hardest APs BTW but just be warned it’s similar to a first semester General Chemistry class. Any university or lac within the top50 will make AP Chem seem routine. However in college you’ll only have 3 or 4 other classes to handle at the same time.
Since you’re already taking another science senior year, there’s no harm in dropping the class. 4 APs + Honor Environnemental Science is a solid courseload.
Fall senior year is busy with college applications which take up as much time as an extra, intense class - focusing on those (and getting enough sleep) matters way more.
That being said, make sure you have 2 colleges that share enough characteristics with your favorite schools AND admit 40% applicants + apply to your flagships and their honors colleges. Do these apps by the EA or priority deadline.