It's always about trust. Do I trust Apple more than Meta right now? Yes. Do I trust them for the next 10 years? Who knows.
But Apple is the one holding all your data and by keeping other companies out, they have a monopoly on that data.
It's like saying you mustn't buy 3rd party car replacement parts because now other companies could track on which parts are replaced. If you do not allow 3rd parties, the car company is the one having your data.
And saying "buy another car" is valid due to the number of manufacturers. But it's iOS vs. Android. So either be locked in the iOS ecosystem and fully trust Apple or let Google get your data but have more choice for 3rd party add-ons.
The only competition is Huawei's HarmonyOS but apart from that, all manufacturers rely on Google.
Apple's statement against the DMA is just them trying to maintain their monopoly. If you think it's about privacy, see where data is stored for Chinese users. And if the US requires Apple to stop end-to-end encryption, Apple will not hesitate to give governments your data. Privacy is just a convenience as Apple doesn't rely on data gathering like Google does
It’s funny you bring up cars… auto manufacturers of course leading the charge on explicitly refusing to open up telemetry data to Apple and Google. Sure, they say it’s to protect the data, to prevent their secrets from being stolen… that also may be true, even if cynical… but that sure isn’t stopping them from taking that data themselves. Oh well. That’s the benefit of controlling your own product.