Lockscreen

So I have this I would say unusual problem. On my DELL laptop, when I type something in for example Microsoft Word, sometimes Windows would suddenly go black screen, and after about 5 seconds show lock screen and I have to press enter (not enter password like on startup) to go back to writing...

When in lock screen, the screen turns off in just a few seconds. I would like to keep the screen ON for custom time, say 20 mins before it turns off. is it possible by any macOS command ? other than apps like keepyouawake etc ?