Plain values are joined with "; " in one cell; lists of objects become columns like items[1].name.

Open JSON in Excel

Excel cannot open JSON as it is. Drop it here and it becomes a table with a column per field.

Steps

Drop the .json (or .jsonl) file on "Convert JSON to CSV".
The largest list inside becomes the table; nested fields become columns like address.city.
Save as Excel or CSV.

Lists inside lists?: Plain values are joined with "; " in one cell; lists of objects become columns like items[1].name.

The CSV is never sent anywhere; everything runs in this browser.