Email is hard to self host, I setup mailcow on a server and delivery has been iffy. For non-production email, pretty good.
Most of the important email on my custom domains are through mxroute.com. Considering Black Friday is coming soon, you can expect a very good offer. I spend 30$ for 3 years to host unlimited mailboxes as long as it is completely under 100GB.
You need to get a domain elsewhere (tld-list.com can help with getting the cheapest price) and setting it up through mxroute is usually a 5-10 minute activity (including DNS setup).
if you're willing to pay, just get an email through microsoft, you'll spend a lot of time and headache making a selfhosted email server work the right way consistently, it's not a good choice for business/money making if that's what this is for.
If you don't need a dedicated mailbox, just buy the domain from a provider like cloudflare or Google that supports email forwarding. Google forwards all emails to @mydomain to my Gmail account for free.
If you also need outgoing email, sign up for an SMTP relay. I use mailjet, and their free tier offers high enough limits for my personal use. Within Gmail, I added the SMTP settings from mailjet, and I can now send email from my custom email address by just selecting it in the compose page.
You don’t even need to register the domain through Cloudflare, you can just set up Cloudflare as the DNS master, and they’ll put in the right DNS records when you configure Email forwarding.
This. Cloudflare also has this relay option that I use for my domain. We have got to start telling people to stop hosting their own mail server and just use a relay. It’s far too much of a headache.
If you want to send mail from your custom domain from within Gmail, you need to use an SMTP relay like mailjet, mailgun, sendgrid, etc. Most have free tiers with high enough sending limits per month that are more than enough for personal use.
I feel most people agree that the one thing that is too much hassle to actually selfhost if you're not really into it is hosting your on own mail, so if you're up for it there are a lot if privacy respecting services out there that give you email (and calender, contacts, filesymc etc) for not too much money with your own domain. I'd probably have a look at Tuta or Mailbox.org first.