My solution is a mesh stuff sack that closes with a drawstring and toggle. It's light and durable, it keeps things together, and I don't leave random possessions behind when I disembark. My partner and I have been traveling with the same sacks for decades.
When I board, I drop the sack on my seat and stow my backpack in the overhead. I then sit with the sack sandwiched between my back and seat. Flight attendants never ask me to stow it.
Once I'm settled, the sack and its contents fit in the pouch along with the safety card and airline magazine.
The contents of the sack depend on the length of journey, level of service, and available charging ports:
Charger or external battery pack
One or two Ziploc bags
(e.g., for coins, or nuts smuggled out of airline clubs)
Lip balm (because the air is dry in a plane)
Pen (to fill out a landing card)
Small packet of Kleenex