Thanks for staying with me 
This what I see at Gmail:
SPF: NEUTRAL with IP 2a02:c207:2070:5720:0:0:0:1
DKIM: ‘FAIL’ with domain e2ee.im
Isn’t this DKIM failure a problem?
As you suggested, I sent 2 more emails with original subjects and messages typed on my keyboard instead of just “test” for the subject and my default signature.
They both landed in Gmail Inbox.
A third and a fourth, made in the same way as those two but also including the signature (just text, “best regards”) went to spam.