It's true it is harder; definitely much harder if you're not a sysadmin by trade. These days to get mail to deliver you not only need to support SMTP, but also TLS, SPF, DKIM, DMARC at a minimum. You also need to make sure that you aren't inadvertently a source for relaying, or non delivery report (NDR) / delivery status notification (DSN) bounce source (vis a vis spam with faked return paths etc).
In short if you don't / won't / can't do the above you are indeed much better paying someone else to do it (preferably at scale with attention to detail like fastmail).
I used to do all these things (not that I am a sysadmin by trade, but after 15 years you get to know the job). Even doing all this the big email players (Microsoft in particular, but Yahoo and Google are also guilty) will just ditch your emails without rhyme or reason if it is not coming out of a known email service.
This didn’t used to happen, but it looks like they have now outsourced their spam filtering to the email service providers who now act as the gatekeepers to email ecosystem - email from a known service == good, email from business that has been around for more than a decade == spam.
In short if you don't / won't / can't do the above you are indeed much better paying someone else to do it (preferably at scale with attention to detail like fastmail).