scroll-pg sɣur MW

Scroll page up & down with F1/2, to top withCtrl & F1and to bottom with Ctrl & F2.

Recommended to reassign these to your preferred input

to operate unfocused its suggested to use Autohotkey.
Eg Below:

f1::
PgUP::
winGetClass, Active_WinClass , A
mouseGetPos, , , Mouse_hWnd
winGetClass, Mouse_WinClass , ahk_id %Mouse_hWnd%
if ( Active_WinClass != Mouse_WinClass ) { ; unfocused
if (Mouse_WinClass in "MozillaWindowClass1,MozillaCompositorWindowClass1,Chrome_WidgetWin_1") {
ControlSend, ahk_parent, {f1}, ahk_class %Mouse_WinClass%
} else
ControlSend, ahk_parent, {f1}, ahk_class %Active_WinClass%
}
else ControlSend, ahk_parent, {f1}, ahk_class %Active_WinClass%
return