None. As long as it’s “commercially available”, their interest is no longer aligned with yours.

Also, unless you are running your own Lemmy instance, I question your assumptions that using Lemmy is actually an upgrade to privacy and data ownership. I heard this point a lot and I don’t see the basis for this. Can you explain?

A small lemmy instance = a small dataset = less desirable to advertisers = less valuable for the owner of the instance to attempt to sell

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.

Even if you run your own instance, if you’re federated with other instances then your posts, comments and upvotes could still be scraped by someone else