Can’t downgrade my iCloud+ plan …

I decided to upgrade my 200GB to 2TB … but I don’t use more than 120GB storage in ICloud.. so no way I’m spending that money on something I don’t use…

so I want to go back to 200GB… I have tried downgrading but when selecting the 200GB, it greyed out and doesn’t let me change… why? And how can I solve it?? I’m thinking just not paying my monthly fee, but I am afraid Apple delete my account or my pictures on iCloud 😭 thanks in advance