Unfortunately, there is one thing all 3D printing filaments have in common: they do not provide adhesion.
Muscle strength alone is not enough to lift a heavy object (glass of water) that slips and falls.
Flexible filaments are a little better than rigid ones because the crushing increases the contact area, but it’s hardly better.
The grip must be provided by an additional material, to allow a full glass of water to be lifted without it slipping.
We have tested all kinds of solutions, from glue to finger cots, and are always looking for the cure-all.
For now our recommendation goes to PlastiDip, aerosol or gel.
To provide the device with the best possible grip, you need to cover your fingertips and palm.