Newborn struggle with sleep

Hi mommies!

I’m a ftm and it’s been hard to get my little one (who is almost 3 weeks old) to fall asleep/stay asleep. Obviously, she’s tired. I put her down after nursing within her wake window and she’ll close her eyes for a bit but eventually opens her eyes again. She’ll keep her eyes open for a good 20-40 mins and then she’ll start fussing. Then the cycle starts all over with us trying to soothe her to sleep. She’s better at night but during the day, she’ll go 5 hours without a nap. It’s a constant battle! Any advice and suggestions would be greatly appreciated!