I'm so sorry about little Scarlett, my hear goes out to you. It wasn't your fault or your lights at all. Any dragon that goes downhill from day 1 was most likely sick when you got it. A beardie vendor may raise all their own, none of their own or swap with other breeders for a variety. Unfortunately you probably got one that was already sick. My condolences to you. Don't use any of the tank decor for your other dragon.
Thank you for your advice and I will not. She ate initially the first day and then just declined immediately. Sebastion (my older beardie) I know didn't eat first few days or week and eventually gave in and now he's a big boy that I can take out with me on adventures and takes in the sunlight a lot happier with me. Scarlet will always hold a place in my heart. Even at work it's hard but I appreciate the advice and feedback.
Yes it's normal to feel the sadness + grief even when you've had one for a short time, they are so small, vulnerable and endearing. It's good to hear that your other dragon Sebastian has grown up to be a big strong fella though, hopefully he'll be with you for many years of adventures.
I am so sorry to hear about your little one, Scarlett, so suddenly too. It is definitely not your fault
& she may have already been ill when you got her. My sincere condolences to you.