To be more precise, you need a free ADC pin and a 1% pull up resistor (4.7k 1% is the default for Klipper) to 3.3V.
Not impossible that an ADC pin is available but you need to be able to read a schematic and a datasheet as well as be familiar with soldering on an SMT board for you to be successful.
It would probably be easier to buy a new main controller board.
You’re way too fast. @pierre286 never told us, which way he wants to go.
New printer board or the original one.
If he goes with the original printer board “and” wants to use a thermistor “and” has an ADC pin available, then we could talk about how to connect the thermistor to the original STM32F103RCT6.