Can't send an email to DJI support due to SPF and DKIM

This is a grumble about the state of the email. Hosting your own mailserver is a pain-in-the butt when things go wrong.

In this case, DJI is "proxying" the email via their server, trying to impersonate your server :) and then the next server in line drops the email, because a failed DMARC/SPF/DKIM policy.

:(

I wonder what are your best practices for SPF/DKIM/DMARC for best compatibility with other parties?