A hotplate most cheaply has the following settings:

More expensively, the two elements would be of slightly different resistances (lengths) and could provide 3a and 3b which switch in one of the differing elements. This will give an extra heat setting.

Most expensively, a thermostat would be inserted in series with a single element for finer control of the temperature. The temperature of the pot would then cycle in a narrow range.

Temperature would initially increase in an exponential function, saturating when energy supplied into the pot equals the energy radiated by the pot.

On disconnecting, the temperature of the pot would decrease in a negative exponential function flooring when the temperature of the pot matched the room temperature.

You can also try with a embedded system board for regulating the supply

OR: high power dc.stepper controller (like a PWM) , brushless DC motors are expensive

Dear Isidoro,

I suggest you to see attached files.

Best regards