Morale isn’t pizza. It’s people believing the work matters and the plan makes sense.

Food and perks are pleasant and last about an afternoon. What keeps a group willing is the sense that the effort leads somewhere and that whoever is in charge has thought it through. When those are missing, treats read as a substitute for them, and people notice the trade immediately. Nobody has ever been talked out of pointlessness with a snack.

Rather than planning something fun, explain to your group where this is going and why the next step follows. Fix one part of the plan that everybody privately thinks is silly. Then order the pizza, because it is still nice.