Satan is still the ruler of this world - for a limited time. There will be a world-wide evil dictatorial government which will demand to be worshipped. There will be a terrible period of seven years (the tribulation) before the visible return of Christ, which will be the end of Satan’s dominion over the world. Why all this must take place is a mystery, but it is certain to happen exactly as the Bible describes it.
Hope that Satan isn’t really the ruler of this world—for a limited time.
Moreover, at almost 61 years of age, I’d hate to think that most of the remainder of my life will be forsaken by the terrible seven years TRIBULATION that you describe.
Much of the Bible is perhaps essentially a mystery, which just makes understanding and accepting Satan’s dominion all the more difficult.