Win 10 latest build won't hibernate

Maybe :)

perhaps that's why I run an ltsb 2016 version (v1607) of Win10 on an old Dell Inspiron 640m/e1405 laptop (yup, the laptop I'm using is few years older than OP's Dell laptop) - and hardly ever had any hibernation problems

perhaps some advanced power settings need to be fine tuned
or maybe some certain network adapters & onboard graphics can't handle the hibernation option in newer win10 versions

I do have a spare western digital WD2500BEVT hard drive where I am currently beta testing win10 pro v1903 (build 18362.53) on there. I'll check if the sleep & hibernation options work on the Dell e1405 laptop