abelsromero wrote

You can unset a value (https://asciidoctor.org/docs/user-manual/#using-attributes-set-assign-and-reference) using :!source-linenums-option: or :source-linenums-option!:.
But keep in mind this changes the value of the attribute from that point on. So if you want to disable it only in some parts, you have to set it again after.