I believe you're looking for something like this
https://www.amazon.com/Hagen-Terra-Reptile-Dimming-Thermostat/dp/B0711KV72C/ref=sr\_1\_9?keywords=dimming+thermostat+reptile&qid=1674748830&sprefix=dimming+thermostat%2Caps%2C102&sr=8-9&ufe=app\_do%3Aamzn1.fos.18ed3cb5-28d5-4975-8bc7-93deae8f9840