Three weeks is a wonder week I think...do you have the book or app? It's a brain or developmental milestone which leaves babies unsettled.

Dd used to cry 7-9pm and seriously nothing really helped, she just grew out of it suddenly at 12 weeks.

I used to sing, pat , rock, bathe etc but the best thing was really just getting outside for a while (summer baby).

Otherwise watch tv with captions and just hold bubs until they're settled. That's all I did with ds and he grew out of it also.