Sorry, but I think you're missing the main point.
The risk is not to be tracked, the issue is embrace, extend, and extinguish (EEE): https://en.m.wikipedia.org/wiki/Embrace,_extend,_and_extinguish
They are currently competing with Twitter and Bluesky, they just need users to kickstart their new platform. That's where the fediverse comes in. All Meta has to do is to convince the instances to give them users.
Meta has a lot of money to throw at UX, they will design a better one than Mastodon. Their instance will also be more reliable (since they have money for lots of computational resources). This will allow them to spread their influence on the fediverse (so that people follow others on Threads), growing up to be the largest instance, and then just defederate from everyone else to βstop spamβ. People will then move to Threads so they keep following their friends there (because their friends signed up for meta, since it was all compatible anyway).
And only then, they will start to harvest data and put ads in front of you.