I'd agree. Measuring "precise" temperature isn't necessarily challenging, but thermostatic control involves understanding, to some degree, the dynamics and transfer function of the system.
Precise thermostatic control requires much more understanding than "small, simple precise thermostat" describes.
Given that the OP still hasn't even described what the application is, how can anyone realistically answer the mail without knowing the complexity of the temperature control and plant part of "thermostat"?
TTFN
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