Why can't DoesQA find this Shadow DOM element?

Prefix your CSS Selector with >>>. If the control is inside Shadow DOM, a normal CSS Selector stays outside that tree and the step cannot find it.

Open the Element (from the failing Test Step, or from Assets → Elements).
Set Element configuration to Manual and Type to CSS.
Put >>> at the start of the Selector, then the CSS for the control. Example: change h1.main-title to >>>h1.main-title.
Save the Element and run the Flow again.

In the browser developer tools, confirm the control sits under a #shadow-root before you change the Selector. If Touch still cannot click after the Selector matches, see Why can't DoesQA click this element?.

For the full how-to, see Shadow DOM in the docs.

If it still fails, create a ticket and include the page URL plus the Element Selector you tried.