Okay, if you're not willing to get remote support, I can also provide you phone support.
OR I will help you in question and answer mode.
IF you had configured your Gmail account with POP settings on the old device, it means old emails were already downloaded to that device and those would stay on that device if you change your password ***** not.
These downloaded emails on the old device can be deleted manually only.
However, if you had just accessed your emails by visiting www.gmail.com or setup your old device using IMAP settings, then the emails will not be available on the old device once you changed password.
In this case, I suggest you to do the following:
And the delete old useless emails.
Also, I 'm ready to provide you phone support. Please let me know.
I realize that this answer may not be entirely to your liking, and I regret being the bearer of information that you really don’t want to hear. But it would be unfair to you and unprofessional of me were I to provide you with anything less than truthful and honest information. I hope you understand and will not blame me by leaving negative rating(poor/bad).
Thank you, ***** *****