Four in active use (I switch between them) - Kindle Oasis 2017 and 2019, Nook Glowlight Plus 2019, Kobo Libra. I also have a Kindle Voyage which I rarely use but can't bring myself to sell, and two old basic Kindles from 2011 and 2012, which I no longer use but haven't sold for sentimental reasons (they were my first ereaders).
Sold my Oasis 2016 and Kindle Basic 2014.
Do I need so many ereaders? Of course not. It's pure gadget lust, I have no excuses. And it's MobileRead's fault I'm an ereader addict now.