I work as a Sysadmin for a web host who sells VPS's. I've helped many people setup domains on their server to cover SPF, DKIM and DMARC passes on a daily basis. Most use these for personal or business level mail delivery without issue.

Are there hurdles to overcome? Sure. But it's not exactly hard as long as you have a IP that's isnt a poor reputation (which as an ISP we help delist and improve). But it's not impossible.

Its more "convenient" to use a third party mail provider just as Office365 since you pass on all that setup and responsibility onto their framework, but it's not hard to setup a decent level of mail service yourself.