Google's John Mueller said there is no need to worry about duplicate content when you are migrating content from one site to another. John said on Twitter "there's no need to worry about duplicate content if you're migrating it from one site to another."
There's no need to worry about duplicate content if you're migrating it from one site to another.
— 🍌 John 🍌 (@JohnMu) July 19, 2020
Google in general doesn't want you to worry too much about duplicate content. But yea, if you are looking to rank for a specific keyword, it is best you have one solid page around that keyword than 100 different pages around that same keyword.
Forum discussion at Twitter.