Insert two values in SXA custom search query token (ResolveSearchQueryTokensProcessor)

I am working with a custom SXA search query token. I want to Insert with two different values.

foreach (var val in values)
  {
     args.Models.Insert(i, this.BuildModel(itemFieldName, val));
  }
args.Models.Remove(model);

SearchStringModel:

protected virtual SearchStringModel BuildModel(string fieldName, string value)
{
  var name = fieldName;
  return new SearchStringModel("custom", FormattableString.Invariant(FormattableStringFactory.Create("{0}|{1}", name, value)))
  {
    Operation = "must"
  };
}

But this logic is not showing search results. Is there any way to achieve this functionality?

protected virtual SearchStringModel BuildModel(string fieldName, string value)
{
  var name = fieldName;
  return new SearchStringModel("custom", FormattableString.Invariant(FormattableStringFactory.Create("{0}|{1}", name, value)))
  {
    Operation = "should"
  };
}