I've had a google and there's hundreds of ICs that seem to do it
Yes there are. There is no one good solution and all are a bit tricky to use because they require a printed circuit and correct layout which you are unlikely to get right first / second or fifth time. I have not known a professional engineer get it right first time.
You are better off buying one as a ready built module. There are lots of these as well so a lot depends on where you are and what supplier you like to use. Look for DC to DC converter modules.