I have a Uniqlo 3 Way Bag which fills the larger laptop + 1-3 night shoulder style carry bag at a budget price and also has a backpack mode. It is pretty lightweight though the front zip pocket could use an internal gusset. I use packing cubes and organizer to separate clothing from cables. Alas, it isn't being sold this season
https://packhacker.com/travel-gear/uniqlo/3-way-bag/
Timbuk2 makes a similar convertible bag
https://www.timbuk2.com/products/355...fcase-backpack Black $149
https://www.timbuk2.com/products/355...39461868797994 Light Grey $89 Final Sale
So does Topo Designs which is going to be colorful.
I like my Uniqlo bag's main opening better, as it doesn't unzip fully so I can rummage through it while using it as shoulder bag. It's slimmer than a tote and shaped more like the boarding bags pre 2000's like
without the U shaped opening. Perhaps you have a messenger bag, similar shaped "boston bag", or perfectly sized tote which could be enhanced with a laptop sleeve & cable pouch?
It looks like LeSportSac is having a sale. Must. Resist.