I think the most volume-for-weight efficient pots are roughly equal height-diameter, which may or may not suit one's particular kit. Your stove type and burner configuration could favor something wider and there's the issue of what you stow in the pot when it's packed.

Generally, shorter, wider pots are the most fuel-efficient so fuel weight enters the equation. An effective windscreen adds further efficiency.

Aluminum and titanium seem on par weightwise, with Ti winning the strength comparison. I tend to cook more than boil, and Ti is trickier than Al due to hotspots. It takes extra effort to avoid scorching.

In sum, IMHO it's best practice to evaluate the complete kitchen when selecting the pot and cup. How do they fit together in the smallest possible packed space? How do the stove and pot work together?

One more observation: Aluminum cups are awful for hot drinks. Ti or plastic will avoid blistered lips.

Cheers,