Simmulated Panel Heater switch level needed

[ArnolddeBolster]

I have a panel heater which i now can control with simmulated dimmer switch device handler but it would be nice to have one which suits better.
It could almost be a copy of the simmulated dimmer switch but with a level slider in scale degrees e.g. 15 - 30 Celsius and with the bullets in sequence of eg 18, 19, 20, 21, 22, degrees Celsius,
Now I use 10% = 18, 30% = 19, 50% = 20 etc.

Is there anybody who is capable to add such device in the github ?

I have no programming experience