There is no way to tell this accurately without additional hardware as there are no connections from the PSU which send that data (and indeed I doubt its being monitored in the PSU). You may be able to estimate it based on state of charge of the battery and consumption but it will likely be crude.

There must be multiple ways to externally monitor power draw using a device on the input to the PSU. One way would be to use an ESP8266/ESP32 based power controller that includes power draw monitoring. I've had good success using Shelly 1pm devices (https://www.shelly.com/en/products/shop/shelly-plus-1-pm) which can be easily read using http requests and/or MQTT. I have no doubt there are other cheaper brands which do exactly the same thing or can be made to do so using Tasmota - but I use Shelly's because they are easy and permitted in my country. Welcome to the world of IOT devices.

Note there is almost certainly a level of disconnect between your usage and what the battery is doing - so depending on your use case (ie the why) and your hardware this may be an XY problem. Its noteworthy that USB-C and even many older laptops have a negotiation of maximum charge rate between the laptop and charger - maybe you can take advantage of this and use a lower amp charger that negotiates max charge rate?