I have speculated before that Top Writer status is what leads to instant curation. That's what happened for me and I've only been here since March 2021. I'm not someone who "started" a mile ahead of everyone else in the Medium game.
I would be frustrated if Medium had said only people who joined in 2018 could be TWs and then only TWs get curation. But if "newbies" like me can earn TW status and get instant curation, then it is about putting in the work to get TW and then instant curation.
Thus, the formula might just be writing "quality" work that gets eyeballs, which leads to TW status, and then leads to curation (assuming my theory is true).