Filter rules does not block the main document itself. It only blocks subrequests. Currently, one way to block a certain website is using $empty modifier.
For example, if you add a rule
But what if it has extensions?
video.startappservice.com
req.startappservice.com
imp.startappservice.com
dts.startappservice.com
req.startappservice.com
I tried blocking it but it didn't work
(||video.startappservice.com
||req.startappservice.com
||imp.startappservice.com
||dts.startappservice.com
||req.startappservice.com)
And what about websites like trk.apperol.com & c.o5o4o6.com?