I'm a moisturizer nomad constantly switching between options; please recommend a holy grail product.

I've tried everything on the market that's supposed to be good, but it just sits on the surface and doesn't fix the dryness deep inside... Is there something wrong with my skin? ㅠㅠ I don't want anything too heavy, so I'm looking for something that's just the right amount of moisture. Price doesn't matter; if you have a product you consider a true 'holy grail,' please just share it with me!