They can monitor you as much as they want. Your posts are the last of their interest.

Facebook trackers are very well spread on the internet, so your browser activity can definitely change what you will see in Threads.

Additionally, they monitor your view time, so they can feed you with contents that are more likely to attract your attention.

Finally, the information they got from your Instagram helps them create your home feed to fit your interests.

And only God knows what they can see through WhatsApp.

Ye, if you don’t want to be tracked, then don’t use Meta Services.