Hi ,
The new account you registered with ESU will automatically receive security updates on your computer, but it will show up on the account you registered. I had this issue with my sister's laptop, which she uses with my mother; ESU is registered on my mother's account, but it doesn't show up on my sister's.
I believe that since you registered, you will receive updates, but because it's linked to a Microsoft account, it will show up on the account you created. However, I believe you don't need to access the new account to perform the updates.
https://www.microsoft.com/en-us/windows/extended-security-updates
Give feedback if the information was useful or not.
Thanks