EDIT: its not fitting perfectly, will make a better version of it
You need all the original Parts except the Hook (https://www.printables.com/de/model/551787-chest-mounted-phone-holder), but download the PhoneHolder_A and the Stopper here!
I just superglued the Pins and a bit of the back to the Chest Piece
Its just for the iPhone 13 Pro Max
Support: Tree + Everywhere (but Support Block the Bottom of the Phoneholder otherwise it will look Not Pretty)
Used the Holder and edited it: https://www.thingiverse.com/thing:4750782
Thanks for your Work, Creators!
The author remixed this model.
Holder for iPhone 13 Pro Max instead of Samsung A22 with Stopper