We have done this option.. However the challenge is the customization tab does not use condition logic, so customer can select option for engraving, forget to enter the engraving information and still check out.
In other words, PS allows for user to checkout without ever entering the engraving information.
Here is example of a product with engraving option and no condition logic to prevent user from forgetting to enter the engraving information: https://notredamefinejewelry.com/rings/23-dangle-ring-with-leprechaun-nd-logo-charm.html