I hope you find the motivation to complete your game! I understand where you’re coming from. While we may not be students, each of us has a job, and taking projects to the finish line is certainly a challenge.
Regarding the cargo detachment: You’re actually doing everything right; it’s just that the trigger on the trailer is hard to find. You need to press 'C' or 'CTRL' to crouch and look more carefully for the detachment. It’s a bit unfortunate that we have to explain this to players since it’s clearly a flaw on our part, and it does affect the experience. But no worries, we’ll fix this bug after the jam. Thank you for playing our game!