Can Apple unlock a locked iPhone with out deleting the data?

That depends on which lock we’re discussing...

There are several different things all commonly called locking or unlocking.

There is carrier lock. Carrier lock questions arise with iPhone and rarely if at all with iPad, and most folks don’t grumble about this being unlocked.

How to unlock your iPhone for use with a different carrier - Apple Support

There is the SIM lock, a passcode associated with the SIM card in use, and you’ll need to discuss that with your carrier.

There is the screen rotation lock mechanism: Rotate the screen on your iPhone or iPod touch - Apple Support

There’s the screen auto-lock mechanism. That’s controlled from the Touch ID & passcode or the Face ID & Passcode settings.

There is also Activation Lock. That mechanism is an theft deterrent, and a theft deterrent that was easy to bypass would not be much of a deterrent. You’ll need the password of the associated Apple ID, or the original purchase receipt and matching photo ID and a discussion with Apple Support. If this device was recently purchased and the seller is still available, contact the seller for remediation or for refund. A remote unlock using iCloud is available to the person with the Apple ID holding an Activation Lock, if they’re inclined to unlock this device.

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There is also the passcode lock:

If you forgot the passcode on your iPhone, or your iPhone is disabled - Apple Support

If your device is passcode locked or disabled, it gets wiped as part of the reset—the storage encryption is tied to the passcode.

AFAIK, Apple won't normally unlock a locked phone, so whether or not they'll wipe any of the data on it is irrelevant.