For mine, I used soft carpet like materials to make the phone fit tighter and have less friction with plastic. I printed it in PLA, but going back I think flexible filament would be better.
The main goal of this project was to have a second screen where I can watch Netflix or read something, while I I work on the laptop.
I hope you find this useful, and if so, share it with a friend, leave a tip, or don't, I don't really care. HAVE FUN!
PS. Send me pictures of it if you print it