Is the connector (on the laptop) just a single pin and an outer contact? Any power supplies with ratings like that I've ever seen are multiple outputs. It is certainly straightforward to design a powersupply inside the laptop to accept a range of voltages, it really makes no sense. Your safest route is to buy a new adapter from HP.
Can you take pictures of the adapter showing the information sticker and a picture looking into the end of the connector?
It appears you can get identical replacements from Amazon for not too much money. There seems to be a number of reviews that complain about the reliability of the HP original supplies as well as the replacement supplies. I also looked at USB-C charging and found that using the supplied cable is important as not all USB cables will work for charging. Good luck!