I think turning down the brightness is the key for longer battery life on MXPE because that QHD screen is a major sucker. Most people don't realize how bright this thing is because our eyes adapt quickly. I run my at 20% brightness indoors and it is still brighter than plenty bright indoors. Outdoors at around 50% I am good.
Another thing is to turn off the "Wake on Approach", and turn off the GPS or put it in battery saver mode, until needed by a specific app like maps. At night, automatically turn off sync, data, bluetooth, NFC and wifi using Automate and you will only burn 2-3% in 8-10hr period.
With simple battery management tricks like that I get around 4 hr SOT with 2-2.5 days (yeah, 60 hours is my record so far) off charger or 5-6 hrs SOT with 1-2 days off the charger. You never need to worry about battery life. And did I tell you, if I charge for 15 minutes with turbo charger from empty, I get around 2 hrs of SOT worth of charge!! Its amazing how well the battery on MXPE works but people have some crazy expectations.