Yes, I agree, slight, , chronic overwatering could be part of your issue, as you can see the heavy speed bump leaves and those larger grow pots, but I have seen something that makes me wonder if you don't have another issue with Thirps, or some other insect infestation, as I have circled a few of my observations in your photos. Maybe what I am seeing in some photos may be just the photo and the way I see it, but I would be looking much closer for any invaders into your grow space. The top image (2.jpg) though shows that something maybe there and starting to spread to your other plants. I would also drop the humidity down to about 50-55%. Plants will do fine

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