Drooping seedlings

ensure that you are getting some stem elongation between nodes -- not "stretchy" but healthy elongation -- this will eliminate the light as the cause. can't be overwatering if you only watered once. More drainage amendments will avoid any droop following an irrigation. you can run 300-500% water or more through the pot and shouldn't see droop if it is done properly. 50% perlite or similar in soil or sphagnum peat moss. 33% in coco is sufficient because it has less water-holding capacity per volume. do this and it's virtually impossible to 'drown ' the roots. the O2 deprevation around the roots is what causes the droop. When you vpd is extremely high, you need to reduce your nutrient concentration. This is easy to do with a soilless/hydro contexdt, but with soil, you better fix that environment, because soil's amendments aren't manipulated so easily. your fertilization only provides supplementation to what is in the soil, so there's limited ability to effect change. This can definitely slow or stunt a plant, if it is the case here. Transpiration increases in high vpd, so it takes in more water. more water means more nutes. if it was a healthy concentration before it is no longer a healthy concentration with elevated tranpiration rates compared to before. inevitably build up toxicities in the plant... no, that plant is not ready for a transplant, though the roots may have been growing this week, your plant is still qute small, so it's water needs are low. water habits -- did you water entire pot or give it some preconceived volume of water? The latter being wrong. Always water entire pot till you get a little runoff to ensure the whole things is wet. In soiless you get 10% runoff minimum and that keeps the EC/PH etc at a consistent, relatively known level. fix those if you were not doing it this way. this looks like it's light related, but not enough info to be certain, and overfed a bit. Get it growing healthy andproperly before transplant if you can. if the canopy is as wide as the pot, you may need to pre-empt that. No worries. up-potting should not be to stressful unless you purposely destroy the rootball while doing it, lol.

I zoomed in on the hygrometer. It says 80f temp and 40 RH.

Where is it marked 40% RH?

Okay. I think I know what's going on here. You say you transplanted a week ago?. They why are they in such small pots mate? With transplants. You do 2. 1 from seedlings-1-14days old. Then then next is 2 weeks old till harvest. They look rootbound. So, when u uppot. Roots reach and expand out. Pushing upwards growth. Also, the substrate is very compact no? Add some pebbles or perlite into the next 1. It should stay stressed for that long Since you've no diary. That's all I can advise. No diaries, no details or potentially issues to notice..