As a counterpoint, I host a couple of domains with Dreamhost and have had no such issues. They've been serving the email for my main domain for 15 years and AFAIK I've never had any of those emails go directly to spam within Gmail or elsewhere. I do periodic smoke testing by sending test emails to different place, plus I have a reasonable number of external users making use of the domains for email as well. FWIW I moved all my DNS records to Cloudflare, but that was only in last couple of years.