
As far as i know, the Page Inspection tool is designed to show all fields defined on the table or page, and there is no native AL property AL solution that prevents fields from being visible in the Page Inspection tool.
Visible = False on Page: This hides the field on the page, but does not affect its visibility in the Page Inspection tool.
Using Permissions restriction : You can limit access to the field via permissions, but this doesn't prevent the field from showing in the Page Inspection tool; it just restricts access for certain users. https://yzhums.com/34832/
Other experts may provide better solutions.