How do I use two antennas with a single Bluetooth module? (BLE repeater)

I want to implement a control system I designed for a light electric motorbike. I would like to mount it as professionally as possible on the chassis. It consists of a power system pcb and a SAMC21 development board which I’ll merge later once this all works properly. I have tried screwing it directly on the aluminium chassis but have found that shocks and vibrations from the horn disturbed the system or even destroyed it upon large shocks. Is there a specific way car and motorcycle manufacturers mount their electronics to make their system as robust as possible?

Last week we visited a PCBA factory. We were looking at reflow ovens. A lot of them have a metal conveyor belt the boards sit on. On a double sided board, when you put the board on the metal belt, won’t the metal belt knock components off as they are only held on by paste?