I had all that setup from day one and still ended up in the GMail spam and banned by Microsoft/Outlook.com (which also includes anyone using Office 365 in their workplace for mail)

I assume that's because I had no reputation, although I did start on a DigitalOcean VPS before I learnt about their terrible ongoing reputation for ignore abuse reports. [1]

[1]: https://discourse.mailinabox.email/t/digital-ocean-ips-being...