json transform with xquery 3.1 (saxon 9.7) and xslt. Only doing it in xquery because want it self contained

output.json

{"stuff":{"more":["more stuff!",{"thing":"more stuff!"}]}}

trans.xq

xquery version "3.1";
declare namespace xsl = "http://www.w3.org/1999/XSL/Transform";
let $transformer := <xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
    xmlns:xs="http://www.w3.org/2001/XMLSchema"
    exclude-result-prefixes="xs"
    version="3.0">
    <xsl:template match="text()[. = 'stuff']">more stuff!</xsl:template>
    <xsl:template match="@*|node()">
        <xsl:copy>
            <xsl:apply-templates select="@*|node()"/>
        </xsl:copy>
    </xsl:template>
</xsl:stylesheet>




let $json := '{"stuff": {"more": ["stuff", {"thing": "stuff"}]}}'
(: http://www.w3.org/TR/xpath-functions-31/#func-transform

http://www.saxonica.com/html/documentation/functions/fn/transform.html
:)
return xml-to-json(transform(
  map {
    "stylesheet-node": $transformer,
    "source-node": fn:json-to-xml($json) 
  }
  )?output)