Cannot confirm. I have my own email server setup since years, with dkim, spf, and dmarc all functioning correctly. I score 10/10 on mail tester. My server has never sent spam (I get daily reports of all emails delivered, so I can actually back this statement up), and my emails go directly to spam 100% of the time on all the major platforms.
I send so little email they won’t even tell me why I’m going to spam.
For personal email it’s not such a big deal, I just tell them to check their spam; but for trying to reach customer service in a large corpo for example, it is impossible.