I have an iPhone xs max, can I use two bluetooth headphones
yes, if you have iOS 13 and above plus apple airPods or Beats equipment. look maybe here for a howto:
https://www.gadgetsnow.com/how-to/share-audio-with-two-bluetooth-headphones-using-this-trick-on-apple-iphone-and-ipad/articleshow/77442813.cms