What size tank do you have the peacock mantis in? It is important to give them larger tanks than other mantis shrimp as they get large and smaller tank have thinner glass and those are when the extremely rare occasions of glass breaking occur. 29+ gallons is a good minimum.
They should be provided with pvc pipe to be turned into their den, as it better replicates their home in the wild. You should try to make it U-shaped with at least 2 exits, and there should be a spot where absolutely no light gets in. This will allow them to have stress free molts.
My peacock mantis is in his own tank, so the light in his tank is solely for my viewing pleasure, and to stimulate a light cycle. I have a small LED zetlight and keep it at 40% strength at its strongest. Their eyesight is so good that the light serves them no real purpose to them, just makes the tank looks nice!
Shell rot is a largely unknown disease, and there is no proof of correlation between light strength and shell rot. Aim to keep water as clean and stable as possible.
They are great though! Can’t get enough of my guy and agree with you that you get very Used to the constant clicking, enjoy!