We, selfhosters and sysadmins alike, need to change our tune around the position of "do not self host email." It only serves to keep email in the grip of big tech. Yes it is difficult and someone without any experience shouldn't start there but it is definitely manageable and not nearly as hard as it is made out to be.
There are multiple email "distributions" nowadays making the software stack set up and maintenance effectively an exercise in running a regular Linux distro upgrade. Mailinabox and mailcow to name two off the top of my head.
The DNS records are relatively straightforward to set up and validate with these mail distros, they basically tell you what to put and provide ways of validating you did what they said you should. There are also many ways to test that you set them up properly by having a service validate them via email you send to the testing service, e.g. mail-tester.com and dmarctester.com, finally DMARC has a report function builtin so you can get regular delivery reports that come directly from the servers that are choosing what to do with your email giving you a clear signal when there are problems.
You don't have to jump into hard mode around a clean IP either you can offload that for a nominal fee to an email service provider if you don't want to try your luck, e.g. MXroute.com has a one time fee for multiple domains.
Yes email is convulted and confusing at times and scary to host given how essential it is but I'd encourage anyone with the time and desire to do it.
Right you said that above and that is what resulted in my larger response. Reiterating without any more information doesn't really change your position in a tangible way. I appreciate that is your stance and many others' stance. I think we need to encourage the opposite to change the landscape of the internet.