To clarify: it's not hard to set it up. It'll just be useless because all your emails to people will be marked as spam. And it takes years to have a chance at getting a good enough "algorithmic reputation" to be pulled out of that bin.
The state of email is disappointing and sad. It is possibly one of the most centralized decentralized protocols/networks on the planet. We need a good replacement for it. It's so legacy.
My email is not landing in spam for people I do business with, others need to add me to white list, do you think this is a problem? I don't, I believe more of us are self hosting less of a problem this will be.
You said that you're hosting since 2011, which makes sense since you're essentially grandfathered in.
If you have set up a new system without any reputation now, even if you have set up DKIM and SPF, it's now a lot worse. Major providers like Google and Microsoft won't really tell you, but if you are new but don't have a dedicated AS and instead you're using (for example) Linode you'll be scored lower by having low-cost solutions that just so happens to be abused by spammers.
As ever with these discussions, I host my own email on a Hetzner VM with https://mailu.io/ and there was no special setup or precaution required to ensure delivery both ways.
Still - if you self-host just assume at some point it will go down and you may have to deal with a backup restore before you can receive any more email. If that gets in the way of your life, you may want to reconsider :)
Recently, a shared hosting company where I had the emails went off-the-grid in a puff. I know I should have taken backups, but, it seems trivial that why would a company just shut off the servers/ stop responding if the service has been impeccable for last 5 years? This is another story.
So, what can I do to just keep a backup of all my emails (one @gmail.com and other personal website emails)?
Maybe for me, just having those emails accessible somewhere is more important (other than primary source/ provider)
Worst advise. If you are incapable (no offence) to set up your own email server, doesn't mean anyone else should avoid doing it.
Source: Having own email server for 17 years. Absolutely happy with it. Again, that doesn't mean everyone should do it, but I'd abstain from advices like you should not! or should do same.
I'm perfectly capable, as is the vast majority of even passing readers of HN. If you think that the hard part is setting up the mail server, you're exactly the type of person that should _not_ be hosting it yourself. The problem is, and always has been, deliverability.
Deliverability _is_ a part of setting everything properly. Setting up mail is not juts installing exim and expecting everything will work by some magic and the manual online.
I do host mail for tens of domains and never had issues with deliverability.
