I would start by making dedicated paragraph style for your TOC. Then in the nested styles section of the TOC paragraph styles dialogue box, set up a nested style for an invisible character style up through one space. To create the invisible character style, use no stokre, no fill and set the point size to something really small, like 0.1 point.
That will make the digits disappear.
If you need the digits permanently gone, so they won’t show up in the bookmakers when you export to PDF, use a GREP search to remove all the digits at the beginning of the paragraphs. You’ll have to run that GREP search each time you regenerate the TOC. A GREP person likely lurking here in the forums will be able to provide you the proper GREP to do what you need.
But if PDF bookmarks are of no concern, use the nested styles trick mentioned first.