I am trying to roman numeral pages 5, 6 & 7 so I go to Numbering and Section Options and choose Roman numerals in the drop down while I highlight pages 5, 6 & 7. The three pages get roman numerals but it changes my TOC where the pages numbers the TOC refers to change to Roman numerals as well.
That is how page numbers work. What ever format your pages numbers are in will show in the TOC.
Usually this is used for say prefix and appendix etc as these should have different number styles.
But is you want to use Roman numerals on the page and arabic numerals on the TOC I thin you will need to add the page number manually to these pages and don’t touch the Numbering and Section Options