Hi my name is ***** ***** I will be the expert working with you today to help and resolve the problem you have posted.
Please open control panel and then Power options
Besides the power plan selected click on the change option
make sure the sleep option for battery and power cord are not set to Never and there is a time set for both the categories for sleep
Make the time bit shorter maybe 2 minutes just for testing...save changes
once done, leave the computer untouched for 3-4 minutes and check if it goes to sleep or not
let me know and i will suggest further accordingly
when you leave it powered on on which screen are you on windows 10 right now let me know that.
alright let me know once you are back.