Some more details on how Instagram is planning to build an ActivityPub compatible service... https://www.theverge.com/2023/5/19/23730070/instagram-twitter-app-competitor-leak
This is Instagram’s new Twitter competitor

A leaked marketing slide from Lia Haberman gives us our first look at Instagram’s upcoming “text-based” app that’s supposed to take on Twitter.

The Verge
@mmasnick How I read that is that it's only one way: if you stay on Instagram where they can track you, you'll be allowed a room with a window to see out. But I've not seen that it works the other direction. I haven't seen the claim that people without an Instagram account could see posts from people there.
@michaelc @mmasnick From the article : “Soon, our app will be compatible with certain other apps like Mastodon,” Instagram’s slide says. “Users on these other apps will be able to search for, follow and interact with your profile and content if you’re public, or if you’re private and approve them as followers.”
So it appears it is both ways.
(either that or only fediverse users can see instagram content, wich would not be useful to meta)