My plant look unhappy

Overwatering

Not enough info. So a bunch of wild guesses ensue... The dark veins in the leaves hint at root zone or water quality issue. Are you letting water 'sit' to reduce chlorine? Don't do that, you are just stagnating your water, if so. That can cause dark veins among other things. Whether it's soilless or soil will impact proper watering habits, but mostly the same (notes for soilless included) 1) fully saturate (get 10% runoff, if soilless, religiously.. it is one of the most important aspects of proper soilless growing, don't scoff at it) 2) wait for appropriate dryback and repeat. Loss of weight is a better trigger than dryness up top, but both can work well. Don't water too soon and all is well. I'd suggest at least 50% loss of weight if not more early on to promot root growth - don't let it wilt. Obvioulsy that would be waiting too long. Frequent fertigation setups wait for 33% loss of weight, so it really doesn't take much to avoid drowning roots. don't do that unless properly set up for frequent fertigation in soilless, of course. just mentioned as a reference. Rough estimate of weight loss is accurate enough.. i.e. going by feel. If you irrigate at same loss of weight it requires a similar and predictable volume of water. Which leads to - do not whimsically choose teh volume of water to give.. you give what is required to accomplish step 1 above. if you want less perlite floating to top, water more slowly, but it's inevitable the top few inches are not as well constituted as below, but roots shouldn't be in that top layer or very few of them anyway if watering properly. Superficial roots are a sign of poor watering habits. Proper constitution - 50% perlite or similkar for high-water capacity mediums and for low-capacity medium like coco coir you only need 33%... in the end they'll all hold a similar amount of water per volume, which is the goal... the particular solid it is absorbed into is one of the least important factors compared to gas:water mixture that resutls... Watering habits are best practices established for most potted plants long before this hobby plant market, and marijuana does not deviate from. Don't try to reinvent the wheel. It looks like it is across all your plants, so it's something applied to all of them in similar ways. did you amp up th elight recently? Even if 1-2 weeks ago, if giving slightly too much eventually they will droop just like this. Giving too much DLI relative to other environmental variables will eventually cause droopy plants... it may even look healthy/fine for 2 weeks before it does so. You tried to give good info, so don't take this the wrong way, but what was provided only allows for wild speculation... hopefully something clicks given the fact you have more info available to you in regard to recent behaviour. If the irrigation deviated greatly, good chance that's at least part of the problem.. if you change dthe lights in any way, that is also a consideration.. They don't look overfed, so i don't think nutrition is the cause.. but the darker veins are less than idea and hint at underlying issues related to irrigation.

Lack of magnesium due to overwatering… this implies to back up your light or to lower the intensity during 2 weeks, the time it recovers.

It looks like you are dealing with overwatering and a lack of oxygen at the root zone. When the growing medium stays constantly wet, the spaces between the soil particles remain filled with water instead of air. This suffocates the roots, preventing them from absorbing oxygen and effectively drawing up nutrients. Paradoxically, a plant that is drowning will often look wilted or droopy, similar to an underwatered plant, because the damaged roots can no longer function properly. Here is what you should do to fix it: 1. Let it dry out: Stop watering immediately. Allow the top few inches of the medium to dry out completely before you even think about watering again. The pot should feel light when you lift it. 2. Improve drainage: Make sure your pots have adequate drainage holes at the bottom so excess water can escape. Never let the pots sit in stagnant runoff water. 3. Introduce wet/dry cycles: Cannabis thrives on a distinct wet and dry cycle. Water thoroughly until you get a bit of runoff, and then wait until the medium dries out before watering again. 4. Boost root oxygen (for the future): If your soil is too dense, the roots will always struggle for air. For your next grow, make sure to mix in plenty of perlite (around 20-30%) to improve aeration and drainage. For now, you can gently poke a few holes in the topsoil with a chopstick to help some air get down there, but be careful not to damage the main root structure. Give her a few days to dry out and breathe, and you should see the leaves perk back up!

Looks like oversaturation of medium possible compression, causing oxyben depletion. Check soil temps anything over 74F is problem.