You can OC without testing stability but if you go around changing the core, cache and ram without stressing any of them along the way what are you going to do when it crashes? Start all over?
I can boot with 200mhz more core than what I have now, I can't imagine just setting some stuff and assuming it was ok.
Auto is fine for most things just not the Auto overclocking crap as you'll end up with an unstable system or way too much voltage all over the place.
Getting the core 100% stable is essential if you don't like getting various crashes and fiddling with the BIOS till you sort it out.
I was about to type out a long list of directions but it's already been done along with the explanations for why:
Overclocking Kaby and Coffee lake is the same procedure hence the guide.
The voltages I wouldn't leave on auto are the input, core and cache.
If you aren't overclocking anything you can just set everything to it's default value manually, if nothing has been changed it should tell you what they are in the BIOS.
For stock performance stock setting are just fine but there is often much more voltage than is needed. Auto settings tend to over do things when we stress overclocks but for stock systems there is no need to stress it so that will never happen.