I don’t know what Airtable’s and Google’s rules are for delivering emails, but if you’re sending using the Gmail action, the email is being sent from your connected Google account. Did you log into your connected Google account and check your “Sent Mail” folder to see if the email was sent?
If you can’t get it to work with Airtable’s automations, you can always give it a try with Make’s Gmail Automations.
There is a small learning curve with Make, which is why I created this basic navigation video to help. I also provide the links to a few other Make training resources there as well.