Which is kind of my point. Even on Lemmy the "data ownership" isn't really up to the individual users, it's the instance owners. The only way to 100% control where your data goes (as an user) and who looks at it, is if you run your own instance. Otherwise you are still at the mercy of another master, hopefully a more benevolent one.
And if the instance that most new users default to is lemmy.world and that instance is 100K users strong, I think the "smaller instance" argument doesn't really apply there for most users.
Do a search on mobile and you need to scroll through an ENTIRE SCREEN full of ads (4-5) to get to the first result. And even that might be SEO'd. That's the current sad state of affairs.