It’s quite likely that any given IP, unless you get one from shady VPS provider or something, is “clean”. And if it’s not it’s usually not that big of a deal to get it cleared from major blacklists (spamhaus, google and microsoft covers quite a lot). You just need to dig up proper forms to tell them that you’re a new owner of said IP and promise to play nice.

Same goes with domain names, but if you get a new one that’s a non-issue. Just set up SPF-records properly (and preferably DKIM/DMARC, but those aren’t strictly necessary and need a bit more than a single TXT-record) and you’re good to go.

And then you of course need to stay away from those lists. If you configure your SMTP to act as a open proxy you’ll be on every shitlist on the planet pretty quickly. So, reasonable measures against compromised account (passwords, firewalls, rate limits…) and against other threats (misconfigured/unsafe web service used for spam and stuff like that). Any of those alone are not too difficult to accomplish, but there’s quite a few things you need to get right.