You don't generally need to license Arm chips unless you are designing your own chips for sale, like STM32 or Raspberry Pi do. This is something very few companies do, relative to those who just build things from existing chips.

If you're just building something with an existing Arm microcontrollers. The vendor (Like STMicro) has already licensed the Arm design and sold it to you.

You just buy the microcontrollers and put them on your custom PCB.

The devkits aren’t suitable for resale but there’s no additional licence when you buy an ARM micro from pretty much any manufacturer.