Sorry, I should have mentioned that additional "tricks" are required. For example, you can insert a style separator at the end of the text and then insert your SEQ field.

Introduction<style separator>{ SEQ Chapter }

To add the style separator, you can press Ctrl+Alt+Enter. When adding it, be sure that you have nonprinting marks displayed (for that you can use the ¶ button on the Home tab). The separator looks like a pilcrow, ¶, surrounded by a dotted line.

In the TOC, only include the paragraph style applied to the left of the style separator. To get numbering in the TOC, you can add it to the TOC 1 style.

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Stefan Blom
Microsoft Word MVP

Microsoft 365 apps for business
Windows 11 Professional