The account is likely still around and valid, you just forgot to update the email address. You can easily change the email address on an account so you only ever need use one account (mine is 20 years old).
● Help with a lost Apple ID or password:
• For help with a forgotten Apple ID (this is likely an active email address or one used in the past), click here --> If you forgot your Apple ID - Apple Support
• For help with a forgotten Apple ID password, click here --> If you forgot your Apple ID password - Apple Support
Apple can completely reset a device if a person can provide sufficient evidence of valid ownership. Do this online 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. Prior to this service being offered officially and moved online, Apple typically required 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