Not sure if this will help you or not, but what do you get when you run this command?
winrm get winrm/config/Winrs
On Win10 I see "MaxShellRunTime = 2147483647". The site you referred to says the default is 28800000 which is 8 hours. Does your system show 28800000?
I found registry entries at HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\WSMAN\WinRS but MaxShellRunTime is not there.
I also tried to update the value, but winrm complained that it was a deprecated setting. You could try that.
winrm set winrm/config/WinRs @{MaxShellRunTime="2147483647"}