Lol, you talk about security and then use clients whose DMs are still leaking metadata even after two years of better solutions out there. Your OS doesn't even allow apps to run Tor and VPNs correctly so that you can be private. And you can't verify any security in iOS because it's closed source. The "Apple security requirements" is just marketing.
Also, Apple has an ad platform. Facebook has to use Apple's trackers so that Apple can sell ads. Also, Google buys Apple data for 25B dollars a year, which is about 20% of all Apple products. Apple tracks you and sells it to Google. Or do you really think Google pays Apple that much just to be the default search on iOS? Turn your brains on. You have been brainwashed.