Ok, I realized that I could still access Forgotten Wilds with my existing save, I just needed to go to a specific place on the map and talk to someone. Still a little wonky and I've lost some of my perks and equipment. I may just wait for the new game as I definitely need a refresher on which arrow types are supposed to be used against specific types of enemies (you don't want to know how many times I died to the first DLC enemy). As much as I really love games with combat systems like this when I'm playing them, it makes coming back to them later far less intuitive than I'd like.