So there is no built-in option or DropDown like for initial ScreenResolution?
As far as I know,
Initial screen resolution also made by 3rd party.
Maybe you are referring to something else or maybe I get it wrong.
I MUST use a 3rd party program/utility?
NO you do not have to.
You can figure out to disable Screensaver internally and contribute with your findings.
And we can add your findings to projects properly so everyone benefits from your discovery.
Reminding, these are all Contribution Hobby Projects.