In general, posting when your followers are online is key, because the Instagram algorithm prioritizes recency. This means that, if all else is equal, a newer post will show up higher on the newsfeed than an older one.
What happens after 10k followers on Instagram?
Once you have 10k followers, Instagram will make it easier for you to get people to your website via Stories with the swipe up to link feature. Swipe up is the only way to get a direct link from your Instagram to your other web properties. And, it’s available in STORIES, if you have 10k followers.