I must have noise to go along with going to sleep. Usually thats an audio book or long-form video essay type YouTube videos. I wear one earbud to bed if I’m sleeping at night with my girlfriend or just blare it from the TV if I’m sleeping alone during the day (rotating shift). I feel like when I don’t have engaging audio and I’m trying to sleep I can’t quiet my mind enough to sleep. A fan or random ambient noise isn’t enough for me.
It takes practice, like anything else. Doing something makes you better at something and not doing something will make you worse at it. In this case you have been conditioning your brain to need ambient noise. There is a line between it being a small help on some days and it being a crutch you’ve built your life around. Sounds lile you are in the latter camp.