I don’t know why anyone is surprised that it’s not the native app. I buy a MacBook because it’s great for media processing and creation, but I still use non native software to do that. The camera app is designed to function simply for the level of familiarity with cameras that ‘most’ people have. Heck, half of the people who complain about the lack of options probably wouldn’t know what to do with a more robust feature set.
Apple has said this multiple times. They could easily update the stock camera app to include a lot more advanced features, but they don’t want to.
The stock camera app works great for 99% of people, and still has enough extra settings to accommodate most power users too. For those that really need the additional settings/freedom there’s more than enough apps in the App Store, like Apple themselves use too.