"Absence of evidence is not evidence of absence".

[Angrboda]

Dark energy

"Dark energy" is just a label for something whose nature is unknown, but that we know it has to exist because of its physical effects (see for example here or here). So "dark energy" (whatever it is) is detectable, albeit in an indirect way.

We infer its presence, because we detect gravitational and inflationary effects consistent with its existence. This may not be a result of dark energy. What would it mean for you to have just said that we detect something that isn't there, in that case? It would mean you are using the word detect in a non-standard and unorthodox sense. Nice try. Equivocation noted and refused.

This is why evidence isn't limited to detection. And this is why your statement is wrong. We have evidence of the existence of dark energy. We can't detect it. If we could, it would no longer be dark energy.

(Note that there have been many inferred scientific facts that proved wrong, from the luminiferous ether to the corpuscular theory of light. Inference from evidence is not detection.)