Here’s how I accomplish what I understand you to want: a slice that includes all columns but only displays select, possibly-reordered columns in a form view.
Add a virtual column to the table of type Show and category Page_Header. Set the Show? property to the formula,
FALSE. This will hide the page and any columns on the page in form views, but have no effect on the visibility of those columns elsewhere.
Create a slice on the table and include all columns.
Reorder columns you want hidden on forms below the Show column created in (1), above. This places those columns on the Show page, hiding them by merit that the page itself will be hidden.
Reorder the columns that remain above the hidden Show page column as desired for presentation on the form.
Myself, I do this for almost all tables, and virtually never reference actual the tables in expressions or views.