Upload the HTML exports from Instagram, then see your mutuals and the accounts that do not follow you back. Processing stays in your browser.
followers_and_following folder.following.html as Following and followers_1.html as Followers above.“Only in A” means accounts you follow that are absent from your followers export. “Only in B” means followers you do not currently follow.
The parser runs in the current browser tab and only reads profile links from the files you choose. Do not create a share link for an export containing information you would not send to another person.