How can I edit and set styles or prevent the standards from being cost-neutral or options outside the styles from being selectable?
In the options menu head to styles and use the three dotted menu on the right to adjust the general style settings.
Next to show details on the far right you will find the three dots menu where you can enter the editor of the style.
Next to the name you can decide to force buyers to choose a style which is the right thing to do when there should be no individual options.
Usually the default options are free to the buyer, but it might be true that you set a free default per style, e.g. when your styles feature the same product but only with different colors.
Once you forced your buyers to choose a style, you could still allow them to change another style in particular product groups connected to that style. This means that after choosing a style and therefor a product in e.g. 10 product groups, only in one of them you would now allow them to just pic another product of a different style.