You have to differentiate between “gifted” and “sold”. Not all of these weapons are gifted and in total it is a small amount relative t Germans budget.

The main damage is that Germany is actively working to destroy the rule based international order it helped to build, which will also backfire on trade, climate protection and other areas requiring upholding international rules.

Aside from that it is a complete moral and historical failure that Germany involves itself in another genocide, proving it had learned nothing from its history.