What they want is to get rid of apps like YouTube Vanced that are making them lose money (and other Play Store apps)
what about us losing control over our own devices? do you like losing control over devices you paid for?
You are inadvertently reaching the true core of the question. The ones who have "control" over a device, are those who control the software running on it. Be it the bad guys (in the case of a malware-infested device), a giant corporation (in the case of a locked-down device), or yourself (when you can install and replace any software you want on the device).
I think this is what commenters here are missing. I agree politically with the notion that people should own their devices (having full control), but the reality is not and will never be that the majority have anything but the illusion of control. Meanwhile, as these devices become increasingly necessary for people to exist at all, and the data they store becomes increasingly sensitive, the ability to theoretically install your own software is completely irrelevant compared to the risk of anything bad happening.
Things that would be compromised if my phone is compromised: All private communication, bank accounts, stock portfolio, medical history, driver's license, criminal record, sexual history, grocery habits, all communication between my government and me, real estate deeds and mortgages, two-factor authentication keys, and I suppose my Steam library.
Like, that's a lot. People can lose their homes. The stakes are unfathomably high here.
Why and how is this protecting against a malicious actors? You can't skip that part.
What about malicious actors that are entrenched, like Meta and even Google? Does this not strengthen them?
I can't say whether the specific implementation will be an improvement, but that is clearly the intent.
Meta and Google have not shown themselves to be "malicious" in sense that is relevant to this discussions. Whatever shady practices they may or may not have is very likely entirely within the law, and they are strongly motivated to protect people's personal data, because they will not have users (i.e., their product) if their platforms are insecure.