With most cars you get the option to fold the backseat. In the examples above the 308 SW has 660/1775 liters, the Karoq has 521/1810 liters.

As you can see the Karoq offers marginally more space only with the seats folded. But that to me feels like an exceptional usage scenario rather than the rule. With the seats up the difference is pretty massive (the SW has ~30% more cargo space) and I think this is the more useful number if you're interested in cargo space. If you want a higher driving position, or better ground clearance, etc. a SW won't really do it.