I get between 40-46 hours usually at the minute. Between 5-7 hours screen on time at permanent 60% brightness, and plenty of usage. Don't use facebook app very much at all mind. Lots of email checking, messaging, up to 2 hours of music daily (play music streaming), checking news apps and so on.
I have rooted and deleted/frozen plenty of bloatware, flashed Simple Kernel v5, turned all animations etc off to try and eek out every bit of usage I can though. But honestly, it's an amazing phone, I came from a Nexus 4 too. Some tasteful mods and tweaks and it's even more of a monster.