it's set to turn off the screen only
1 I have not seen that option before. I have only seen: do nothing, sleep, hibernate, shutdown.
And if it was set to turn off the screen only then why do you say it used to sleep it?
I am concerned that we are talking at cross-purposes.
2 And please post the response to this command [cmd or PS window, it doesn't matter] so your available power-sleep states are known.
PowerCfg -a
That response might say that you have S0 Low power idle [S0 Modern standby].
3 I'd also like to check your other power plan settings - Display off after, Sleep after, Hibernate after.
4 I expect to suggest that you test behaviour
- in Safe mode
- in another user account
so please tell me if you have already tried them.
5 Personally, I would go ahead and reinstall my display driver even if it is the same version as the one currently installed.
There is no diagnostic test for a corrupted display driver so I just reinstall it if there is a related problem [such as sleep misbehaviour] just to eliminate it as a possible cause. Your computer maker should provide a display driver for download & install.
Denis