I want to delete my subscription to iCloud 2/ 50 GM of storage for .99/month as I have Apple One which includes 200 GB of storage

See the following Apple Support article for information on Apple One and iCloud storage: What happens to your iCloud storage when you sign up for Apple One - Apple Support including the following:

If both are using the same Apple ID:

If the iCloud storage included in Apple One is more than your current plan

Your current iCloud+ plan is canceled and you'll receive a pro-rated refund. Your total iCloud storage will be the amount included in your Apple One subscription.

or

If you use one Apple ID for iCloud storage and one for Apple Media subscriptions, learn what to do.

Sharing an iCloud Storage plan is optional. You can share or not share any iCloud storage plan. Also see: Share iCloud+ with your family - Apple Support

What if you already have a personal 2TB cloud storage that is nearly full and you want to now (also) subscribe to a family apple One? Is this additional storage for the family?