I’m not trying to denigrate you, but “real” products produced at moderate scale will source their own microcontrollers/microprocessors, have their own pcb design, and have the BOM cost-optimized.
A Raspberry Pi or Arduino is fine for early prototyping and hobbyists, but if you’re going to make a million of something then you aren’t going to stuff a Raspberry Pi in your product unless the ecosystem is one of your selling points. Otherwise, using a Raspberry Pi means that you’re paying for USB ports, Ethernet ports, WiFi, Bluetooth, led lights, header pins, and every other component on the board and your produce probably doesn’t need them all. Including a bunch of components that you aren’t using is just leaving profit on the table.
A Raspberry Pi or Arduino is fine for early prototyping and hobbyists, but if you’re going to make a million of something then you aren’t going to stuff a Raspberry Pi in your product unless the ecosystem is one of your selling points. Otherwise, using a Raspberry Pi means that you’re paying for USB ports, Ethernet ports, WiFi, Bluetooth, led lights, header pins, and every other component on the board and your produce probably doesn’t need them all. Including a bunch of components that you aren’t using is just leaving profit on the table.