No source on dread.
https://telegram.org/privacy#5-6-no-ads-based-on-user-data
https://telegram.org/privacy#11-changes-to-this-privacy-policy
And nothing mentioned on that subject in official telegram privacy policy
Discussion
I mean, their own link includes this. I think this article is FUD. https://nostrcheck.me/media/public/nostrcheck.me_2509028683132690581689171517.webp