Alternatively pay for a GSuite account for like £3 a month (Or Office 365) and all of this is handled for you with superior spam filtering, search, webmail, no manual administration and no issues with email delivery due to other filters thinking your server is a bit dodgy. It's too much effort to run your own email server well.
Of even better, use some smaller alternative that is not Google (mailbox.org, protonmail, fastmail, ...). GMail's de-facto monopoly on email (and especially spam filtering) is a threat to the Internet.
I tried registering this domain through G Suite and Zoho first, but they both said my domain had a TLD that's commonly used by spammers, and refused to bind it. Zoho eventually made an exception but took over a week for them to get back to me.