There is a pervasive myth that independent voters determine elections. More "identify" as independents in polling. But most of those routinely vote D or R. (They don't behave as independents; they just prefer the label.)
Only 7% don't lean either way and a lot of them don't usually vote.
Elections are driven mostly by turnout. 55% are D or independents who routinely vote D.
Source:
https://www.pewresearch.org/politics/2019/03/14/political-independents-who-they-are-what-they-think/