  Navigating the intricacies of thermal management at the quantum scale is a
challenge in the pursuit of advanced nanoscale technologies. To this extent,
theoretical frameworks introducing minimal models mirroring the functionality
of electronic current amplifiers and transistors, for instance, have been
proposed. Different architectures of the subsystems composing a quantum thermal
device can be considered, tacitly bringing drawbacks or advantages if properly
engineered. This paper extends the prior research on thermotronics, studying a
strongly coupled three-subsystem thermal device with a specific emphasis on a
third excited level in the control subsystem. Our setup can be employed as a
multipurpose device conditioned on the specific choice of internal parameters:
heat switch, rectifier, stabilizer, and amplifier. The exploration of the
detuned levels unveils a key role in the performance and working regime of the
device. We observe a stable and strong amplification effect persisting over
broad ranges of temperature. We conclude that considering a three-level system,
as the one directly in contact with the control temperature, boosts output
currents and the ability to operate our devices as a switch at various
temperatures.
