Convert Apple Subscriptions to Apple One
Can I upgrade my Apple Subscriptions to Apple One or do I have to sign up for Apple One and cancel Apple Music, News etc?
See the following from Get Apple One - Apple Support
If you already subscribe to Apple Music, Apple News+, Apple Arcade, or Apple TV+, you don't need to cancel those subscriptions. They will automatically be canceled when you're billed for Apple One.
and also see:
What happens to your iCloud storage plan when you sign up for Apple One - Apple Support