I’m the goofy lady who flies internationally with 2 neck wallets - my normal one plus another for my passport. It’s less stressful to have the important stuff on me (though stashing in backpack is an option if it gets uncomfortable).
I sometimes put a drawstring backpack in the side pouch of my backpack. That allows me to keep my kindle, a few snacks etc with me if i decide to put backpack in overhead compartment. Later in the trip it can work well for stashing a jacket when inside at a museum.