It is mentioned in in https://www.olimex.com/Products/IoT/ESP32-S3/ESP32-S3-DevKit-Lipo/open-source-hardware that the power consumption is about 200 uA where CH340X takes about 50-150 uA.
In order to cut down ESP32-S3 power consumption, the CH340X could be unpowered by e.g. cutting some foil in PCB. Is there a clear point in PCB where this could be done or even jumper that could be unsoldered?
Unfortunately, it is impossible to circumvent the CH340x even with hardware modification. The CH340X is directly connected to the 3.3V line and disabling that would also disable the powering of the module.