Bosch or varta are usually the pick of the brands. I could be wrong but I believe the coding is only necessary if the battery has different parameters to the one you have now (capacity, type etc).
Easiest swap is to look at what you have now and replace it like for like.
Your car is five years old, not unexpected to need a new battery by now.
This is not correct. You should always code a new battery! They way the battery is charged changes as it gets old. When you put a new battery, you should code it in order for the car to know that has a new battery and restart the "charging method".
This sholud be done in order to maximize the battery life. Of course that you can replace a battery without coding and it will work. The car "sees" 12 V, it works.
I don't understand why Bosch batteries are one of the firsts to be mentioned because I never saw a car with a genuine battery made by Bosch. I'm not saying that Bosch batteries are rubbish, but at least for manufacturers they are not a choice.
Varta, Exide, Moll, Fiamm, Banner. This five brands are OE suppliers. If the genuine is too much I would choose one of these.