What’s wrong with my plant

After -> before(3 days ago)

I am completely new to gardening, please help me out, I feel like crying because I think I killed them.

I started the bird’s eye chili plant from seed in solo cups indoors with grow lights 4 weeks ago, they started sprouting 3 weeks and I transplanted 2 of them in 10 gallon grow bag 5 days ago(i was lazy and I didn’t want to buy a bunch of small intermediary pots). They were potted in a Miracle grow potting mix with epsoma Tomatotone mixed into it, I watered them once with miracle grow all purpose right when they were planted.

I started hardening them(they are going to be in my apartment balcony with grow lights for additional light), but have been indoors with grow lights for the last two days since the temperature dropped outside.

I did unfortunately forget to turn off the grow lights a day ago( they were on for 18 hours) and as a result I saw some slightly curled crispy edged leaf that was droopy, I watered them and they perked up. But now I am noticing the young leaves are very pale yellowing from middle, slight purples and droopy.

My plant hasn’t grown taller than 2 inches (I assumed it was because they were in solo cups, but they are only 3-4 weeks tall). I most definitely might have overwatered the grow bags when I first transplanted, but have reduced since then. What else should I be doing now? How to fix it? Is it too far gone?