Having unique content as much as possible is the best thing to do. This way IG won’t see common things on both accounts. As you mentioned you are doing it in chronological order.
I don’t think that my personal photos and videos can be seen as “common”. I’ve only shared them once, years ago. Some of my content is from 2013-2014, mostly photos from my travels. I don’t think it’ll be in an issue. Not to mention I’m modifying them.
So far everything is going well. The old account seems to be messed up. I keep getting a “Couldn’t load users” error whenever I check my Followers list. It says I have 1 close friend, but when I open the list, there are none. Something is not right. And the overall trust score of the account is not ok as well, so it’s easier to just start over. With Reels, I can easily grow it from scratch.