Unable to log in Apple ID "iPhone is locked owner"

Unless you can get her to unlock it with her Apple ID and password your only alternative is to ask Apple to reset it. Apple can completely reset a device if a person can provide sufficient evidence of valid ownership. Check the requirements and steps at: Activation Lock support request - https://al-support.apple.com/#/additional-support Apple says, "Proof of ownership documentation is required," but does not detail what currently constitutes proof other than it “must include the product serial number, IMEI or MEID.” Apple may typically require the original receipt* issued by Apple or an Apple Authorized Reseller. If Apple resets the device this will give you access to the device but won't restore access to the account used to lock it. There is nothing that can be done to expedite an Activation Lock request.

*Apple recommends you "Keep your receipt after you buy an Apple device" --> Keep your receipt after you buy an Apple device - Apple Support

If your iPhone 7 is still locked with your ex-girlfriend's Apple ID, it's likely linked to her Apple ID via Activation Lock. To resolve this issue, contact the previous owner, provide necessary details, and visit Apple Support. Provide proof of ownership. Alternative methods include checking if the device is still linked, visiting an Apple Store, performing a factory reset without an Apple ID, or using DFU mode for troubleshooting. However, bypassing Activation Lock without the Apple ID credentials is generally not possible due to Apple's robust security measures.