Yes, basically that. I set up mail servers for a company in 2001-2008 and then it was way easier. I tried to do it again five years ago, for my personal server and quickly found the landscape changed a lot. But it is doable.
I do use SPF but I don't use DKIM or DMARC. On the inbound side, I do use greylisting and anti-spam. I don't tend to change my config between releases of debian stable.