My spouse was starting to get some minor back pain, cause unknown, but I suggested that she should stop carrying her computer backpack on her back when riding to work. I attached a large Wald non-folding basket to her rear rack using stainless hose clamps. I believe it's a Wald 585. I've had an identical basket on my commuting bike for almost 20 years and it's still in great shape. Putting some innertube rubber between the rack and basket helps keep the whole thing from rattling.

She just drops her backpack into the basket and puts a bungee over it.

What I did was I got a tiny laptop. At home, it's plugged into a full sized display, keyboard, and mouse. When I want to take it somewhere, I just throw it in a regular student backpack and off I go.