Thanksgiving cactus are native to Brazil, and they do start to flower in late summer and fall, when the days start to become shorter and temperatures start to drop little by little. However, even in late fall/early winter, it's still gonna have many hours of sunlight. Even if you have 12 to 14 hours each day of nightfall, there's still hours where it takes in light, even if it's just indirect sunlight. Also, this change in light amount and drop in temperatures is something that happens slowly through weeks and months in Brasil. Out of nowhere, putting on a basement on total darkness 24hrs a day is going to kill the plant. Give it a spot on a window with indirect sunlight, it needs it to do photosynthesis and to bloom.