GMail email missing on Mac
I have somehow lost all of my Gmail email previous to Sept. 11, 2019. I have had this gmail account for years and had many emails that I was holding on to. I just discovered this issue and am wondering if I have a Time Machine backup before the previously mentioned Sept date, could I recover those emails in Mac Mail?
Google and Gmail assistance is nearly impossible to reach. I have gone through all the steps they suggest in the Help feature but none apply.
Help!
MacBook Air