How do I specify an alternateName for SEO?

How do I specify an `alternateName` in Squarespace? Squarespace is injecting this block with my site's data, without the alternateName field.

<script type="application/ld+json">
  {
    "@context": "https://schema.org",
    "@type": "WebSite",
    "name": "Burnt Toast",
    "alternateName": ["BT", "B-T", "Burnt Toast Shop", "example.com"],
    "url": "https://www.example.com/"
  }
</script>

https://developers.google.com/search/docs/appearance/site-names#:~:text=Add an alternative site name,This is optional.