New Apple ID but still migrate data?

Apple has no formal account merging or transferring process. The things below will help you in doing ongoing or one-time transfer of as much as possible from one account to the other, but some things can never be transferred (namely purchases), only shared.

You can use various iCloud sharing features for some ongoing data sharing.

Share folders with iCloud Drive --> Share files and folders in iCloud Drive on iCloud.com - Apple Support

Read How to use Shared Albums in Photos on your iPhone, iPad, and Mac - Apple Support about how to share photos.

Sharing music playlists —> How to share an Apple Music playlist on your iPhone or iPad - Apple Support

Apps and media bought with one ID are permanently associated with that ID. Look into using Family Sharing to continue to be able to use items purchased with one Apple ID with other Apple IDs, and for some data sharing features.

- Family Sharing - What is Family Sharing? - Apple Support

- Set up Family Sharing - Set up Family Sharing - Apple Support

The next section may sound tricky but it lets you merge some things on a device where you have already signed in with an old account but want to use a new account and incorporate data that is already on the device from the old account. Incidentally, the data will then propagate to other devices using iCloud with that new ID. (I haven't tried this with a computer but it may also work with a computer account signed into an old ID.)

If you have signed into the first ID on a device then fortunately when you sign out of that ID it asks you if you wish to retain the data from the old ID on your device (toggle the ones you want to on). If you keep data on the device then when you sign in with the other ID it will merge this data with the account signing into the device. You can later delete individual items from the old ID that you do not want. Similar information can be found in this post: I have 2 apple IDs i want to merge them h… - Apple Community , and a step-by-step in this User Tip: How to “unshare” an Apple ID - Apple Community . Note that only content physically present on the device like contacts, photos and videos will be retained. Meta data such as a game play scores that are tied to a specific ID or are only on a vendor's Apple ID-specific database remotely will not be retained. Also turn off storage optimization before doing this. With Optimize Storage, smaller, space-saving photos and videos are kept on your device while all of your original, full-resolution versions are stored in iCloud. Make sure photo optimization is turned off so the full quality versions from the old account are actually on the device before merging the content into your new account. Manage your photo and video storage - Apple Support You can turn optimization back on again once you are fully using your new ID on the device.

Even though apps may remain on a device and may work for a while, you will not be able to update them or redownload them unless you buy them again with this ID or download them with this ID using Family Sharing.

Sign out of iCloud on your iPhone, iPad, iPod touch, Apple TV, or Mac --> Sign out of iCloud on your devices - Apple Support

If another Apple ID is signed in you may need to enter the password for that ID to sign out of that ID first.

Click on this link to learn how to 'Sign in with your Apple ID' --> Sign in with your Apple ID - Apple Support

It’s basically this: How to “unshare” an Apple ID - Apple Community

pyrodice wrote:

I'm not sure yet whether that's it or not. I want a complete break from one to the next, no way for tracking cookies or malware or email sign up lists, or spam callers to follow from one number to another, or that one weird ex if you have one...

How far do you want to take this?

Establishing a new and entirely separate identify is an immense effort, and many that try this will compromise their efforts by being predictable and returning to their old habits and old haunts and familiar online communities, or with a continuation of their likes or hobbies, or by associating payment cards across identities, or many other such mistakes.

If you do want to do that, then erase the iPhone and then sell it, maybe after archiving your photos somewhere (and never posting any, etc), and then delete the Apple ID entirely, and acquire and set up with a new device and a new Apple ID and new (probably pay-as-you-go) cellular plan.

Facebook, Google, credit bureaus, tax agents, and other online services are all good at matching identities and relationships.

Being “Lazarus Long” has become immensely more difficult in the last decade or two. Or much more difficult for folks creating backgrounds for espionage agents’ or witness protection program protectees’ cover identities, for that matter.

Otherwise, the “unsharing” above will mostly work.

First you say"

"trying to create a fresh phone account with a different apple ID but still load everything from my current phone"

then you say:

"want a complete break from one to the next"

Which are diametrically opposing.

True privacy is something that disappeared 20 or 30 years ago. You're likely going to be using the same WiFi with the same IP address. That won't tell them it is you but it's a starter. Then you'll maybe visit the same web site and look at the same product. Another clue as to the person. In the end they will figure out it is you. The thing is to stop freaking out about it. I actually manage to keep a fairly low profile, but I rarely buy anything online. Apart from this web site I don't do social media. Still, I get the occasional spam phone calls at home. State agencies have my information and people can get it that way. Look up my house address online and the state lists the owner. Others probably have my age and telephone numbers too. Bingo, I start getting calls targeted at people in my age bracket. They are also clever and fake the phone numbers so they say they are fairly local to me. That's to get me to answer the phone thinking maybe I'll answer it thinking I have just forgotten Bob Martin who supposedly lives 20 miles away is somebody I have simply forgotten but is somebody I need to speak to.

It's the 21st century and there's no getting away from it unless you go live in a hut in the middle of the forest and learn to be self-sustaining. Even then Google Earth will show somebody's living there in its satellite photos.

pyrodice wrote:

I don't *really* expect Temu, political campaign A, B, and C, or my ex of colluding with the IRS... That second one's possible, but would they tip their hand on that just for one dude who doesn't wanna be pestered for his vote? There's a girl on tiktok that gets medicare scammer calls a couple times a day and she's made a career out of answering them with ridiculous business names because she can't get them to stop dialing her number. I feel her pain.

Either “unshare” your data and expect to get matched by the data brokers and advertisers and credit bureaus, or break entirely and cleanly and maintain scrupulous isolation and separation to try to avoid linking your aliases.

Cookies are just a small part of online tracking nowadays, too: https://coveryourtracks.eff.org/

These entities all make money by selling your info, too.

Which means that your ex can pay for a record search, and get a list of your aliases that were incompletely isolated.

If you want to experience the whole genre, search for “how to disappear without a trace” in DDG or Google, and expect those discussions and videos may not include the full list of details that can be collated.