Question about Shadowbans

Hey guys, I am trying to grow 2 ig accs right now, but i am stuck in shadowban. Is there a chance that the reason could be duplicate content, because i have some posts similar to other popular accounts in same niches?
Sorry, if my question is too stupid, but I am completely new in ig, still learning

They're going after dup content specifically. If the same content shows up under many accounts they hide them all to protect against "fake news" bots.

This might be a dumb question but I have a personal account and I test post all of the content I post on it on another account that I have first (that one is set to private), mainly to see how it looks. Should I stop doing that? Will IG recognize it as duplicate content?