Hi, 

I created a magsafe base to items attach to a phone case. The cover is meant to hide a magnet ring one the case while the item base has a metal ring on the bottom. The cover is printed very thin to maximum magnetic hold. You might have to try around with your printer settings or try rafts until you get a sufficiant result. As Magnets on the case I used these:

https://www.amazon.de/dp/B08Q7XWB85

and for the item base these metal rings:

https://www.amazon.de/dp/B09QWG7QYG

Have fun!