Looking for a packable bag for flights

Hey All, I'm looking for a packable bag that I can put into a Tom Bihn Synapse 25 for flights. Trying to not have to put my backpack under the seat in front and have a packable bag within it to carry my ipad, bose headphones, phone, wallet, and maybe some cables and a charger.

Saw the Tom Bihn Side Hustle, but want something with a bit more storage compartments and organization.

Anyone do something similar?