Just published a massive refactoring on the road to full IG support: https://git.sr.ht/~cloutier/bird.makeup/commit/b6f7dd61b8f970f0b9af0f6b51771fb6e7852add
This makes it so that the concept of followers is not hard-coded to twitter anymore but can switch dynamically. This has fixed the followers information in the profile page and is necessary in the crawling mode to sent post to the correct followers.
I think there is 2-3 refactoring of that size left and then the crawling will work too!