Note, just in case you end up looking at eBags backpacks, such as the "Professional Slim" line, they are NOT lightweight! We own both sizes and never use them. They are bomb-proof for protection, but weigh about half as much empty as full! (Well, maybe 1/3, but way too much.)
https://www.ebags.com/backpacks/travel/pro-slim-weekender/117783XXXX.html?dwvar_117783XXXX_color=Black&cgid=travel-backpacks