I have set up DMARC, SPF, DKIM and whatnot. Sadly no one seems to take this as a signal for a competent mail setup, so Microsoft's mail servers regularly block my mails because of the surrounding IP range reputation - not because any spam would originate from my IPs or domains.
When its unimportant or important to the receiver only, you push responsibility to them: "I sent it. Must be your email that's glithced. Tried Gmail or Proton?"
When its important to you, you use your backup Gmail or Proton account.
