Practice, practice, practice. And maybe try isolating your your fingers, one by one. Meaning, first concentrate on correct index finger placement when strumming, keep it there then add your middle, strum them together then eventually add the final ring finger.
Try not to rush. No shame in taking it slowly. And remember, this isn't just resource for online learning. It's also a library of past tutorials. Look up Lisa McCormick's spider finger exercise to strengthen hand dexterity. That's how I see this website.
I hope this makes enough sense and helps you out of your rut.
Kind regards, Drake.
P.S. no disrespect to Anders or any other instructor, as I've recommended another tutorial. Guitar Tricks is outstanding. I love it here.
Am I the only one who plays multiple instruments? Let's be inspirational and find our muses everyday!