customising options of a screensaver, are determined by the screensaver itself.
if a screensaver has been created to offer options (eg photos screensaver on my Win10 PC, allows me to adjust the 'speed' of the slideshow, and, it allows me to enabled 'shuffle'. There are no other configurable options for this particular screensaver, i.e.
it doesn't offer a 'fade' feature)

the 3DText screensaver, offers a different set of options by comparison

Don [doesn't work for MSFT, and they're probably glad about that ;]