Common chassis ground for all components?

I read the ‘Earth Loop’ documentation which mentioned isolating components from multiple voltage circuits. I realise an opto-isolator may not be suitable for the two-way Rx/Tx communication between oDrive and an Arduino or R-Pi.

My project is a vehicle with an aluminium chassis, could I connect all the components’ Gnd (battery - ) to the chassis? Diagram below.

The type of conductor is not really important. Your goal should always be to achieve is what is called “Star Grounding”:
The ideal layout would be to have all grounds to meet at one point (for example the power supply). Do not connect the output of the DC-DC converter back to the power supply. Isolate your communication (Uart, Step Dir, etc) connections if your Odrive is not powered by a completely separate power supply from your controller.

Here is how you should do it (sry for the crude drawing):

If you want to use your chassis as your ground do it like this:

Note how there is no connection to the chassis ground on the connection between your controller and the DC-DC converter.