Have you tried to set “Start Section” in InDesign files as standard ID documents, not through “Book” option?

You can do it without a script — easy and fast:

1. Select char. styles you want to delete;
2. Click to the recycle bin;
3. Check both check boxes;
4. Click OK.

1. Select para. styles you want to delete;
2. Click to the recycle bin;
3. Select “[No Paragraph Style]” from “and Replace With:”
4. Check both check boxes;
5. Click OK.

You need character style with font style “Regular” and select it under “Bullets and Numbering > Character Style”.

I would do it as a standard facing pages book without inner bleed. I’ve never ever used inner bleed for 30+ years whether it was PageMaker, QuarkXPress, InDesign or now Affinity Publiser and never had any problems with it.
I don’t know what is so special in spiral bounding? I’ve done this kind of books, too without any special treatement.

Watch this video:

Are you trying to create booklet from InDesign or Acrobat?

You selected it when nothing else was selected on the page (no text, no text frame…). To reset it, deselect again everything and click on the “None” char style.

Yes, you can. Just select from the stroke type (thick-thin) bellow the stroke size in Control bar.