I posted this separately, but look into a heated mattress pad too. Its life changing for cold climates. Direct heat into your covers makes it so much cozier.
I stay up later than my wife and like to go to lay in a cool bed. She likes it warm. So we compromised and got a mattress warmer for her, and I have the heat set to drop by several degrees at like 11 PM.
But then she gets up at like 7 AM (6 AM on workdays), and she'd be freezing, so I have the heat set to turn back up at 6 AM, which means if I wake up, I find myself roasting and can't get back to sleep.
What's the temperature in your bedroom? You say "drop by several degrees" (but not from what to what) so it sounds like you heat there during the day and let it drop at 11PM?
Got something like that too! Not sure why I didn't mention it honestly. So in the morning I get out of bed and turn on the air heating so I get dressed in warmth; in the evening I turn on the heated blanket while brushing my teeth and warm up the bed and covers. Also allows me to leave the room colder while not being cold in bed for the first twenty minutes.
I don't know the power draw while it warms up. The packaging says 100W but I measured it to actually use only ~30W, average during 1.5 hours. Maybe it does use 100W the first 5 minutes or so. Let's say it uses the full 100W for up to 15 minutes while I do my evening hygiene ritual as an upper bound, that would be 0.025 kWh (1 cent last year, 2 cents at current prices).