Just saw this! Cosmere wise I think I've read pretty much everything except White Sand (1-3), Mistborn era 2, and The Dark One.
Currently, I know it might be cliche but, I would have to say that I think Rhythm of War is my favorite so far. I feel like I relate to Kaladin some in my struggles with depression sometimes and hearing Hoid say, "You will be warm again." still makes my eyes water. I'm also a massive nerd for worldbuilding so any new lore or new inventions that have the possibility to change things makes a huge impact on me.