Despite having Windows 10 Build 16251, I still often need to reboot my PC upon resuming from sleep/standby UNLESS I choose to NOT let the Wifi disconnect during sleep. This means my PC consumes more power while sleeping, but this is better than having to reboot on most resumes. Here’s how to keep Wifi always on during sleep (it will shut off during hibernate), which works for me nearly 100% of the time on resume.
Note that even “letting Microsoft manage” the Wifi during sleep causes nearly 100% failure of Wifi on resume. Only the “Never” setting has worked for me.