No clue. I was referring to the operating mode of the third party thermostat here.
Most respectable units are switchable between “on/off” aks hysteresis and “chrono proportional” aka TPI. For example:
There are plenty of non TPI options.
You need to read the manuals but vanilla hysteresis stats are available.
Quick look at Screwfix:
Hysteresis only:
Configurable Hysteresis or TPI:
TPI only: