A: You’re not wrong… there are indeed 5 Anomalies to be flipped, and only 4 Event cards that will do the job. The trick is that there are ways to get a card played more than once.
Also, at some point, the deck will get re-shuffled and those 4 cards will come back into the equation. Yes, that can take a while, but being Q is all about playing the long game. And if you don’t want to wait, you can use Rewinds to play Event cards again, though that can be tricky because it can make other players suspect your identity. Best to be patient when you’re Q.
Oh, and there is one other card of note here: the Inverter called Q Snaps His Fingers, which has a secondary function: it also flips an Anchorpoint. Of course, you can use this to undo the spread of the Devron Anomaly instead of increasing it – and other players will suggest you do just that – but you can often get away with doing “what Q would want” with this card without giving away the secret that you actually are Q.
All of this is to say that yes, being Q is tricky — that’s why he’s got 4 pips.