How to prevent Submit button rendering based on Computed value?

Instead of merely hiding it, I'd like to prevent the Submit button from rendering all together based on a Computed Token or Computed Twig. I don't want either the Computed Token/Twig or the Submit button to be visible in the source code. What's the best way to accomplish this?

Let me preface this discussion with the following observation:
Currently in a multi-page form I can prevent elements in Page 1 from rendering if I conditionally hide them based on a Computed element in Page 2. And they won't just be hidden -- they won't render at all -- which is what I want to do with the Submit button. However, because the Submit button is apparently a special element in Webform, it cannot be made the child of any other elements and thus I can only hide it client-side which allows a hacker to make it visible and submit the form anyway (as well as see the expected variable name/value of the Computed Token/Twig because the #states logic is visible in the rendered Submit button code). If I were free to put a Submit button on every page instead of using one common button for the entire form, then I would have a solution, however I get the following error when I try to do that:

The Submit button(s) (webform_actions) is a root element that can not be used as child to another element.

Perhaps this is a feature request. I'm suggesting that it may be useful to have the ability to nest individual Submit buttons on pages for advanced validation, if practical. Otherwise I would appreciate some direction on how I might accomplish this.