What you're describing sounds exactly like colic. The fact that she cries at the same time every day is the biggest red flag - colic has this almost hypnotic thing about presenting itself regularly, usually in the late afternoon or evening. At 3 weeks you're right in the classic period, since they usually start around the second week and can last up to 3-4 months. If you notice that during these episodes her little belly seems tight, she's pulling her legs up toward her chest, or her face is changing color, you've got other indicators pointing to colic rather than other issues.
The important thing is ruling out other causes. Maybe get her checked by the pediatrician to make sure it's not reflux or food intolerances, especially if you're breastfeeding (in that case you might have eaten something that bothers her). But honestly, the pattern you're describing - every evening, same time, you've already tried the basic solutions - is so textbook that it's probably colic. Unfortunately there's no miracle cure, even though some moms swear by certain positions (like the "colic hold" where you hold her belly-down along your forearm), a tube to let the air out, or even just keeping her moving (I know people who've spent hours walking around).
Hang in there, it passes. I know it sounds terrible when you're in the middle of an evening crisis, but it really doesn't last forever. In the meantime, breathe when you can and don't feel guilty if sometimes you put her in the crib and step away for five minutes - it's normal and necessary for your own sanity.