I think im learning things. Would be really cool if someone could explain to me why this is the way it is

So i got diagnosed this month. Struggled with sounds all my life and could barely use my old pc because of the sound of the fans. Since i got a new one thats almost always silent, i didnt have that problem in a long time. I dont like light so i wanted to close my windows and i took a giant fan from my mom to fight the heat that would come with a closed window. The fan was so loud i wasnt able to relax at all and when i tried to play a game, i couldnt concentrate either. I opened a tiktok that i used for the music and a "silence occasionally broken by "thing" " video. Why is stacking more background noise helping??? Why am i not annoyed by the fan anymore huh?? I dont even know how i got the idea to just add more sound. Im so confused, And why does it work? im genuinely curious. I wouldnt have asked if i didnt have a diagnosis already. Im very unsure and sorry if im at the wrong subreddit with that. I have a few things any so little understanding of them, i cant tell what problem belongs where