Hi

While iou voold change your Firefox Account email address for one from Firefox Relay, this is not recommended as Relay email addresses are designed to be disposable.

Need google email address changed for a Firefox one

Not sure what you mean by Firefox one however the company Mozilla (that makes the Firefox web browsers) does not provide a email service to the general public as only those who works for Mozilla in a capacity (as an employee usually) that makes them eligible to get a @mozilla.org email for their duration of involvement.