Can you confirm it's reached FG? 4 days is a long time to start, hope you haven't underpitched. If you have I'd be surprised if it's reached FG with a 5% brew in 10 days.
You can certainly rack into a cube but be careful of your techniques (i.e. sanitised, squirt with CO2, no splashing). The purpose of the 3-4 days at zero is to drop particles out of solution to the bottom of the FV or secondary. Up to you. I personally give it about 10 days at 3°C to drop the last few points for reasons which has been mentioned elsewhere on the forum. THEN cold crash, then store for 3 weeks in the beer fridge before drinking.
Sounds to me like you need a fermenting fridge