Nah, that’s FUD. I had a pretty easy time setting it up myself. You only have to setup SPF, DKIM and DMARC. Which is pretty easy by itself. You even have online services to check that you have set it up everything correctly.
That’s just where you’re getting started. The biggest hurdle is you have no reputation (or worse, you’re on a shared provider giving you negative reputation to start), and you have no good way to build that up as an individual person, and no good way to debug/appeal each case as your emails get rejected as possible spam.
I’m on hetzner. My IP address was in some dnsrbl lists. I appealed and got my ip clean. Now I can send emails to gmail and outlook and they arrive successfully. I don’t see where all this fuss comes. You set up your server according to google and you are good to go. That’s all.