Teach your grandma the same phone setting for the fourth time like it’s the first. She taught you to use a spoon.

Patience with someone learning something slowly is a small repayment on an enormous unpaid debt. Somebody sat with you while you could not tie laces, read a clock, or work a fork, and did it for years without visible irritation. Menus and settings change constantly and were designed by people who already knew where everything was. Struggling with them is not a failing of the person.

Show it again at the speed they need, and write the steps down so they are not dependent on you next time. Sit beside them rather than taking the phone out of their hands.