What is the simplest way for existing Apple subscribers to convert existing services to an Apple One subscription

The problem is that I do not see any way to subscribe to Apple One in lieu or replacement of my various Apple subscriptions. Clicking on my name on iPhone or iPad does not show subscriptions. I can see them on my iMac, but do not have an option to simply replace existing subscriptions with Apple One. Surely it should be simple, using your Apple ID to modify subscriptions to take advantage of cost savings. App,e gets a D minus so far.

The problem I am experiencing is there is no Apple One subscription shown as a choice. So I am unable to sign up for Apple One, which then would merge/cancel my other subscriptions. An advertising effort shows how you can save money by going with a bundle, but that does not help if you cannot first sign up for Apple One. Perhaps it is just a glitch on roll-out, but it would seem to me that inviting existing subscription customers to convert to Apple One would have been both easy and a high priority.