This a remix from an iPhone 6s stand. It's a bit wider and can accommodate thicker phones and phones with cases.

I've added a .f3d file, so you can adjust the model to your likings.

Edit 24.12.2020: After printing, I noticed that unless you're running iPhone with a very small cable, you're unable to charge it, when it's in a vertical position. I've added another .stl file with the arms being higher (.f3d file not updated!) from 16.5mm to 22.5mm. I hope this extra 6mm will be enough (if not please comment so, and I'll try to make it even higher)

Creality

Ender 3 Pro

No

Yes

0.2

25%