Advice on antenna tuning ?

I am currently working to redesign one of our products to include Bluetooth communication for remote control. For this, I am targetting the STM32WBA23.

Given that the PCB is mounted inside a solid, cast-aluminium housing, I will need to put the antenna on a seperate board and connect it with a cable to the main PCB.

My question now is: Where do I put the tuning components? Do I place these on the main PCB, close to the controller, or do I put them on the antenna board?
Or maybe it doesn't actually matter.

I would appreciate any comments and directions by those more RF savvy than me.