I have a tado in a cottage with a radiator heater, it replaces the original indoor thermostat and works perfectly. Now for underfloor heating, there is normally no indoor thermostat as the inertia is too great, it is an outdoor themostat and a measurement of the return temperature of the heating fluid that is used to adjust the room temperature. I think that if you have an indoor thermostat, you can perhaps replace it by a tado but by checking beforehand on the tado website if your heater is compatible (brand and model) if you don't have any indoor thermostat, I don't think that it is possible to install a tado.

It is not the type of heating that is important, but the make and model of the heating. tado replaces the thermostat and controls the boiler, so it must be compatible with the boiler. What do you mean by "manual thermostat"?