Time Machine - Gmail
I was cleaning my Gmail , and deleted the archived e-mails, and found out the hard way that now ALL MY GMAIL is gone.
I do have a time machine back up - will that help me recover ?
iMac 21.5″, macOS 10.15
Please read Restore your Mac from a backup - Apple Support.
Exactly what you deleted is not entirely clear to me, but Time Machine backs up everything on your Mac. If those emails were stored locally "on your Mac" then you can restore them. Refer to this excerpt from Create or delete mailboxes in Mail on Mac - Apple Support:
"If you use Time Machine to back up files on your Mac, you can use it to recover previous versions of a deleted mailbox."