So, you can try very hard to reach that 10, but consider how much extra it will bring you. According to the KIRC research, the difference is nil. Although achieving a 10 is still the ultimate goal.
A disadvantage of having a different version of the NPS for Europe makes benchmarking with companies in other countries more difficult. But ultimately, the reason for asking NPS questions is not to compare yourself with others, but to listen to the customer. And if your customers give an 8 for the same behavior as customers who give you a 10? Why wouldn't you choose a yardstick that matches this?
In addition, it's not just about the score, but more about the stories behind it. Start by asking NPS questions and start analyzing your drivers over time. Which factors influence your NPS, either positively or negatively? And what are you going to do about it? Take action and repeat. This is how you improve your customer's experience!