Why did you create a new Apple account? Read this support article about Apple ID Frequently Asked Questions --> https://appleid.apple.com/faq
"How many Apple IDs do I need?
Just one. Use the same Apple ID everywhere you sign in to ensure that all your Apple services and devices work together seamlessly and you can access your personal content from all your devices."
If you change email address you do NOT need to create a new account. You simply change the address for the old one, but this is getting outside of what you asked.
Unpair and erase your Apple Watch - Apple Support
"Unpairing your Apple Watch restores it to its factory settings." "If you have the iPhone that your Apple Watch is paired with, you should follow the steps to unpair your Apple Watch [click here for directions --> Unpair and erase your Apple Watch - Apple Support ]. This removes Activation Lock from your Apple Watch as well as erasing all its content and settings. If you don't have the paired iPhone, you can erase your Apple Watch [click here for directions --> Unpair and erase your Apple Watch - Apple Support ], but Activation Lock will remain."
You may need to either get the old account working again, or ask Apple to reset the Watch completely.
This Apple article has instructions for what to do if you have forgotten your Apple account password —> If you forgot your Apple ID password - Apple Support
or go directly to this link —> http://iforgot.apple.com/
If you don't receive your verification or reset email, read this Apple Support article: If you didn't receive your verification or reset email - Apple Support
"When you make certain updates to your Apple ID, we’ll send you an email to help you complete the update. For example, you might have reset your password, reset your security questions, or added a new email address to your account."
If you find you can’t sign in, reset your password, or receive verification codes, you can request account recovery (read this support article: How to use account recovery when you can’t reset your Apple ID password - Apple Support ) to regain access to your account. Account recovery might take a few days or longer, depending on the specific account information you can provide to verify your identity. More detail in —> Activation Lockout Issues - Apple Community
If you still need help this page provides country-specific Apple Support contact information for customers seeking help ➞ Contact Apple for support and service - Apple Support
This page has telephone numbers for contacting Apple for support and service ➞ Contact Apple for support and service - 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 new online service Apple typically required the original receipt issued by Apple or an Apple Authorized Reseller and documented provenance (so typically it would be the original owner who does this, or a descendant with legal proof of ownership). 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