Look, this is what I believe is going on and nothing else it can be looking at this pic...
I know you transplanted them, but what's to stop you from doing the same thing again in the new pot, luck?
If the leaves are limp and weak and feel floppy when you try to lift them, wilting and feel thin and will flop around like tissue paper in the wind, then they need water, you are underwatering them. The plants cannot maintain Turgor pressure in their veins holding any juices in there to keep it pumped up. The water hose is dry and sucked in on itself, shrunk capilaries dry and thin veins, need water to pump them up again. Pressurize and pump up the main water hose vein of the plant so it stands strong with leaves pumped up. They need water to function or they will halt all growth and die.
If the leaves are still stiff when you lift them and thick, not floppy like tissue paper, but still hard leaves, just curved down, and you try to uncurve that curved leaf and it's tip, and you feel resistance when you try to lift the leaves up with your hand, and they dont feel weak and thin and floppy, but still pumped up with water in the leaves, thick leathery leaves, then you are overwatering them, they have to dry properly in between waterings. The process of a plant's life needs oxygen at the roots or they will drown in water and the roots will slowly die as the leaves will be overloaded with water while the plant comes to a stand still and wont grow. The plant wont be able to process photosynthesis anymore absorbing light energy and co2 combining to make sugars to fuel any growth. The plant won't grow, and eventually will die if the roots do not have oxygen available to them very long.
Besides the either overwatering, or underwatering, or both, problem, my worry for you is that you are using a very dense soil mix that does not have enoough micro air gaps and spaces in it to hold oxygen for the roots in the first place, that it's a bad soil, and you just transplanted them into that soil once again. If the soil is too dense then anything you put in that soll will always exhibit overwatering symptoms, the roots will never be able to breath properly to fuel any growth. The plant will slowly drown and die.
Certain plants are adapted to live in swamps and directly in water, but those plants have special structures that stick up out of the water for roots to get oxygen. All roots of all plants need oxygen or the roots will die, and then the plant.
Roots breathe oxygen like we do. Plant roots not only absorb water and nutrients for plant growth, but also respire. It is important that the growing medium has enough oxygen for plant roots to function properly.
Oxygen is an essential plant nutrient. Plant root systems require oxygen for aerobic respiration, an essential plant process that releases energy for root growth and nutrient uptake.
Not enough oxygen at the roots lowers the permeability of roots to water and there'll be a buldup of toxins. Water and nutrients won't be uptaked enough for plant growth.
A lot of times fungi can take hold on plants that are stressed by oxygen starvation in the root zone.
Roots dieing will attract disease that will hasten the demise of the plant.
The title of your thread is, "Help diagnose problem".
I hope I have done an adequate job of explaning to you the importance of a good fluffy breathable soil, and why roots need oxygen for all plant functions or the plant will slowly die. There is nothing more important.
By overwatering the plants you are slowly killing them.
This is my diagnoses, grow bro.
