This is true in an ideal sense, but when it comes to phones, you have to look at the whole spectrum of the situation. Given you can sneak a SoC in a phone with backdoor access to everything, can you really ever make it secure? You need open source hardware along with software, and that just isn't where we are at.

Apple is more aligned with privacy than other megacorps, so I trust their hardware more. I don't trust their software, but we need to make compromises in today's world to function.

Android devices, on the other hand, I do not trust at all. Google / Samsung / etc all have high motivations to compromise security for profit, higher than Apple.