How to parse a json (encoded in htmlentities) that was saved

I suppose you wanted me to do something like

No. jsonPath is a Gatling check, not an arbitrary JSON parser. You can’t use Gatling components in your own functions. You have to use standard Java libraries.

.check(
  css("meta[name='myConfig.1']", "content")
    .transform(content => yourOwnJsonParsing(yourOwnHtmlUnescaping(content))
    .saveAs("cacheId")