For several years, I've had an LL Bean Carryall Tote (unfortunately discontinued but can still be found in aftermarket places like Mercari). It has long straps that can be held in your hands or go over your shoulders, but no crossbody strap. It can also slip over the handle of your rolling bag, has a water bottle pocket and a couple of inside pockets.
What I packed in it: Journaling stuff (pens, a 9" x 5" handbound journal, and two smaller journals (pocket size Moleskine; the big journal stays in my room, the others go in my daybag); prescription medications (in small plastic ziplock baggies I bought on Amazon on the advice of somebody in this forum); 3-1-1 bag (there was less in this than ever before. I switched to individual packets of eyeglass cleaner, and did not bring shampoo or conditioner as I used what was on hand at my destinations); eyeglasses; USB cables (in a soft case; I brought four and used three); UK wall adapter and charger with several ports (in a hard case); noise cancelling headphones in hard case (rather large but no way around it that I can see); Fitkick slippers; Colgate Wisps (did not use these at all but have in the past); Samsung Galaxy Lite tablet; smartphone in Built case (I had two phones, one for communication and the other for photography; only one is unlocked). My Tom Bihn Side Kick also fit inside the bag.
I was much happier returning to this bag after I took a Pakt duffel last year (which was semi disastrous). I'm not sure what I would do differently next time. Not take the Wisps (I can easily fit a toothbrush and toothpaste into the bag), perhaps.
I have thought about replacing this bag with a rolling/spinner underseat bag. Particularly if I can find one with a trolley sleeve.