I needed a computing unit for my medical devices. We tried an out-of-the-box phone and a our own phone from scratch. In the end, the out-of-the-box phone won. But only because the business was focused in the medical part and couldn't get distracted with phone stuff.

Apple and Samsung are not really competitors. Sure, they make phones, but not privacy-focused phones. The brand can stand on its own.

You don't need to earn much money at this level, you just need enough to get to the second round of devices that can do bigger volumes.

Many VCs can give you 5M if you have the skill and the real desire to pull this off.