ping-pong ball [gooped to ring-shaped rare-earth magnet] -> stand/handle
electrical tape [adhered to disc-shaped rare-earth magnet]
Temporary: USB-C to USB-A Adapter [integrated with USB-C cable] -> library/airplane/Communauto
Carried separately: Anker 521 Power Bank (PowerCore Fusion) [iPhone + MacBook]
Potential Discovery or Invention
Here is the FlipZip Magnetic Quick-release Phone Mount System, which does not have features like MagSafe charger, USB-C cable, adjustable lanyard or variable-orientation stand.