At night our house is usually 78F in the summer, and 55F in the winter. Our solution is a lightweight down comforter for the summer, and heavier "all season" down comforter for the winter. Sometimes the summer comforter gets layered on as well for particularly cold nights. Unfortunately I don't remember the brand of our lightweight comforter because the tag wore off long ago, but Brooklinen's lightweight comforter consistently gets high marks. It is 650 fill power, which is about the lowest I've seen from luxury brands. You may even want something in 500-600 range, which is generally considered more of a budget comforter.

Key things to look for are a very high thread count, all cotton shell (low thread counts leak feathers), and goose down fill. Also be sure to keep a cover on the comforter since cleaning down is a pain in the butt.

One other thing to consider is getting a wool mattress topper or pad. A lot of people don't realize that moisture regulation is just as important as insulation when it comes to maintaining a comfortable sleeping temperature. Foam mattresses and synthetic fill blankets tend to trap moisture, making it harder for your body to thermoregulate through perspiration. You wake up hot and sweaty in the summer even though you only have a thin blanket over you.

Wool is hands down the best at regulating moisture, but wool blankets tend to be heavy, and if you have enough wool to make a fluffy comforter you're going to roast. You can get the best of both worlds by putting a wool topper under you and a down comforter on top. The wool acts as a buffer, soaking up moisture when the humidity gets too high, and releasing it over time. The down comforter is breathable enough to let moisture out so it doesn't build beyond what the wool topper can handle.

My final bit of advice is don't make your bed in the morning. Fold the comforter and top sheet down to the foot of the bed and brush all the hair, skin flakes, and other bits of human off the bed. Leave the all the bedding exposed to light and air for the entire day. This will give the wool topper a chance to completely dry out, extend the life of your bedding, keep the sheets cleaner and less stinky for longer, and help with allergies if you have them (dust mites need darkness and moisture to survive).