Cargo vehicle is not moving
If the cargo vehicle doesn't move when nobody is close to it, it's completely normal
The cargo will move only if there is at least one player in the area of it, this depends on FiveM mechanics
Heists alerts not working
If you are not receiving any alert when a heist is started, is because you didn't setup any alarm in the heist.
To setup an alarm, you need a step which has the bell icon 🔔, which allows you to setup the alarms.
An example can be the 'hackable panel' or a 'safe'