I share your frustrations with Sci-Fi for our December trip. We went this summer and could not find any availability 60 days out. I signed up for notifications on Sci-Fi and a few other hard to get reservations and got all but Sci-Fi weeks before the trip. However, there were some that showed up the day before, due to people cancelling. Just me - I think Disney holds back a few reservation times for some restaurants and releases the times sporadically, but I do not get the impression that is the case with Sci-Fi. post-COVID. My advice is to sign up for notifications, but be prepared that it is unlikely anything is going to show-up until people cancel a day or two before - check constantly day before and day of and be ready to pounce.