It's not a shadow ban OP. Your posts are simply not at the top. The reason why you're seeing it at the top from your main account (I.e the account used to make the post) is due to a little something called 'preference of content'. It's like making a comment on an instagram post. When you're viewing the post (on a mobile phone for instance), though the post may be having thousands of comments, your comment will be highlighted. But the moment you click on the comments and start viewing the comment section, your comment gets lost in the flood of other comments.
The reason why this isn't a shadow ban is because you can view the post under 'recent' from your alternate IG accounts.
People often confuse this with a shadow ban. It may sound similar but it isn't quite the same.
TL;DR Your posts aren't ranking. IG is simply showing them to you as it's your content and their algo believes you'd like to see it first.
Pro tip : Use a tool to track metrics. I'd suggest one but I've have none.
