niedrige Luftfeuchtigkeit

Different strains enjoy different humiditites, different strains have evolved through the ages in different climates so its good to check prior to growing a strain what it's preference is. There is not too much variation though most plant are happy with 40-50%. Sativa are normally from drier arid climates. Indica enjoy slightly more humid. The humidity at the top of a tent will be around 20 rh higher than the bottom, sometimes more or less depending on temperatures, makes sure if you can to monitor top and bottom. You should aim to really let your soil dry out then water heavily till you have 10% run off. Humidity will rise ESPECIALLY during floweringwhen you water so be prepared not to let it get above 60% or you are asking for trouble if it stagnates too long. Air circulation is key, keep humidity under 50 and if possible 40% this will keep everything in a nice state of continual drying. Humidity over 65 will also greatly reduce photosynthesis as the leaves will close the stomata on back of leaves to prevent "drowning" this will grind all production to a halt and the water uptake through rootzones will cease, soil will stagnate and budrot will appear if left.

I have mine set for 38-42 in late flower. I’ve also grown in low humidity and it’s not an issue

No not at all. it may not be optimal but it will not hurt them. and in flower that's where you want the RH. Good Luck!