You can pair multiple devices, but only one can be connected at a time. I'd be inclined to get a dual-SIM phone, I have a OnePlus 5t and would recommend it.
Thank you a lot for your answer. Unfortunately, I cannot get a dual sim because one phone is a private one, while the other is the company one: they should stay separate.
You could redirect the call from one to the other while you´re in the car, that way you can receive calls on both numbers. May cost extra though, depending on your contract.
You could redirect the call from one to the other while you´re in the car, that way you can receive calls on both numbers. May cost extra though, depending on your contract.