Mac Word receives error messafge fields are nested too deeply

1. manually reduce nesting: 
Press Cmd + F9 to display all field codes in the document (e.g. { IF { REF... }).
Find fields with multiple levels of nesting (e.g. { IF { REF { SEQ... } }) and try to use simple text or static content. } }), try replacing the partial nesting with simple text or static content.
Press Cmd + F9 to switch back to normal view and press F9 to update the field.
2. Split complex fields: 
Split nested fields into multiple independent fields, for example: 
{ IF { REF _Page1 } = "A" } 
Change to: 
{ SET PageRef { REF _Page1 } } 
{ IF { PageRef } = "A" } 
3. Rebuild the structure of the document: 
Copy the content of the non-fields to a new document: 
Create a new blank document, selectively paste the content of the original document (using the Paste Options > Text Only).
Re-insert necessary fields (e.g. table of contents, page numbers) to avoid deep nesting.
Replace Complex Objects: 
Convert the results generated by nested fields to plain text (select the field > Ctrl + Shift + F9 to permanently convert to static text).
Note: This operation removes field associations, so use with caution!
4. Update or fix Office 
Update Word for Mac: 
Open Microsoft AutoUpdate (from the menu bar Help > Check for Updates) and install the latest version.
Microsoft may have optimized the field handling logic in the update.
5. Disable Hardware Acceleration: 
Go to Word > Preferences > General, check “Disable Hardware Graphics Acceleration” and restart Word. 
6. Use Word for Windows to handle 
If the problem persists: 
Open the document in Word for Windows (which usually has better compatibility with nested fields).
Simplify the fields and return to your Mac to continue editing!