Not sure if this is what you need but check it out.

https://docs.q2developer.com/guides/frontend_development/application_level_outlets.html

Found solution:

function inputHandler (event) {
  var query = event.detail.query;
  var optionsArr = Array.prototype.slice.call(this.querySelectorAll('q2-option'));
  
  optionsArr.forEach(function(option) {
    alert(options.value);
  });
}