The US did issue passports with an x gender marker. The first one was issued in 2021 after a lawsuit, and the option was on the official paperwork in 2022. Most would usually advise against doing so as many countries do not recognize the X gender, and would deny entry as a result. Be aware of where you want to travel and that those countries are accepting before you commit to the X marker.

That was before the newest administration. It remains to be seen how things will play out in future as many executive orders will be blocked in the courts. Executive orders are the lowest tier federal legislation, overruled by nearly everything else.