4 times same genetic but one has hanging leaves

Not all plants are the same. If you are giving them the same amount of water and the plant does not have the same root system as the other then it just might not use it all up and still could be over watering. Water as needed. Increase your perlite in the mix to prevent over watering. It does mean you will need to water more frequently but its more controlled in that the medium can only hold onto to so much water and never to much. I don;t think this is a overwatering thing. To my it looks like the only plant that is not slightly droopy is the bottom left in the main pic. all the other are a bit droopy. but look healthy. Higher RH can also make a plant look droopy. and your running 70-80% RH. so I would get more air movent in their and I bet they would perk up a bit. If you keep this high RH in flower it will almost certainly lead to bud rot. Can google something call VPD. its all about RH and Temps and gives a chart to follow. There is no perfect answer but I think something around 1-1.2 is good. https://www.dimluxlighting.com/knowledge/blog/vapor-pressure-deficit-the-ultimate-guide-to-vpd/ Your at 21c/70% in last diary update. so that's a VPD of around. 0.53-0.66 chart says you want to be around 0.8-1.2kpa Good Luck!