I think the best thing is to cycle through a workspace based on what you are doing. As long as you can work on and laptop and out of 1 bag, you are pretty much set.
This can also help prevent workplace injuries as you are not always sitting in the same position. The way I work I get to sit in multiple ergonomic chairs, a standing desk, and even laying down on a sofa.
You want to avoid injuries, so you suggest using the least ergonomic piece of equipment possible?
I do all my work on laptops, but 99% of it is with a monitor, keyboard, and mouse attached at a workstation calibrated to me. Hunching over a laptop is the last thing you should be doing.
This can also help prevent workplace injuries as you are not always sitting in the same position. The way I work I get to sit in multiple ergonomic chairs, a standing desk, and even laying down on a sofa.