[I think this is the right place to ask. I posed this on Apple Discussions then occurred to me it might get better answers here].
I have had an iCloud Apple ID and a Store Apple ID for almost a decade. Lots of reasons for that including side-effects of the .mac and mobile.me migrations, old system constraints, etc.
In theory the iPhone still supports different Store ID and iCloud ID. In practice this is becoming untenable. I run into bugs with iBooks (purchase vs. sync) now and I suspect this will all get worse fast. (2FA, sharing iCloud data plan vs family sharing media, sending money via iMessage, etc).
For years I hoped Apple would provide a fix - a way to merge these Apple IDs. About 2-4 years ago Tim Cook was quoted as saying a fix was coming. I now think a fix is not coming.
I’m looking into reconciling these IDs. I will need to keep the ID associated with my thousands of dollars of Apple product purchases (too bad I can’t shift those virtual purchases – weirdly there used to be an unofficial way to move hardware purchases between Apple IDs). That means I will need to switch my iCloud Apple ID to my Store Apple ID. I’ve read some articles on doing this and I’m building up a list of expected issues. I’ll have to reconstitute our Family Sharing Group for example, repurchase our shared Apple Storage plan on the Store Apple ID, migrate data, delete backups, change Wallet settings, etc. I expect to encounter significant problems.
Anyone have any tips to pass one?
Update: This 2016 article is the best resource I found … mostly things I would have thought of though …https://blog.xojo.com/2013/06/20/merging-icloudapple-id-accounts/