Instagram deleted the IGTV button that was in the top corner of it applications, since no one was using it anyway.
The IGTV button was Instagram's response to YouTube, a separate but not real application for longer videos than allowed. The project started in June 2018 with drumbeats, but apparently did not have the luck that its developers expected.
And that's because you can watch IGTV videos without the app. Essentially the button was meant to give users a shortcut to navigate directly to content IGΤV. So it seems that no one or a few used this button.
Οι περισσότεροι αναζητούν content IGΤV δια μέσω άλλων οδών, όπως μέσω προεπισκόπησης στην Feed, ή από το κανάλι IGTV στο Explore, ή από τα προφίλ των δημιουργών, ακόμα και από την αυτόνομη εφαρμογή. Πολύ λίγοι κάνουν click on icon IGTV in the top right corner of the home screen in the Instagram app.
As they also mention from Instagram, in their attempt to simplify it platform remove this icon based on its non-use and comments from the community.