Milou

Since you are already looking, measure the enclosure properly rather than trusting it. Basking and ambient with a temperature gun and digital probes, a clear gradient, humidity on a hygrometer for your species, and real ventilation.

Respiratory infections in reptiles almost always trace back to that list: too cold, humidity wrong in one direction or the other, poor airflow, a dirty enclosure. Getting the numbers now means that if anything does change you know what moved.

Alert and eating well is doing a lot of work in your post. That is most of the answer.

Those dials measure the air next to the glass and they are routinely out by a lot. Get a cheap infrared gun and shoot the surfaces: basking spot and the floor at the cool end. Mine disagreed with the dial by nine degrees in the direction that mattered.