I send mail directly. I have a public IP address. I had to remove it (a few times) from a list of 'dynamically residential address space'. I have configured the server carefully and implemented SPF, DKIM and DMARC. I have proper revDNS records. Currently my mail doesn't seem to be considered SPAM by Google or others more often than other mails.
When filters consider some mail spam there usually is a reason. The trick is to find the reason and understand how to mitigate it. Some anti-spam measures are not fair (like blanket blocking whole countries or ISPs), but I was lucky enough not to be bothered by those.
I can confirm that 'error' and 'mistake' is the same word in Polish. I don't think it matters here, though. And I am sure that Mr Sikorski knows the difference. His speech, although often harsh, is very diplomatic. When he says 'Trump made a mistake' it can safely be read as 'Trump is a complete idiot'.