No because that is kinda why it is implemented, so you and your whole family can’t use this as an alternative for a proper router/modem. 

I understand, however I am only using it for my own purposes. I am not sharing the connection with anybody. Therefore, does KPN automatically assume I would be using the unlimited plan to share the connection with everybody in my surroundings?

It’s ok, I understand there are people who would do that. So I am stuck with extending the bundle by 2GB everytime I run out? Or is there another workaround for this?

KPN isn’t assuming anything. They just supply the connection in this way to discourage you from using it like a fixed connection. You’re stuck with it, there is no workaround.

Don’t you have access to a fixed modem/router connection? That’s really unlimited.

Thank you for your response. Yes, I do have access to a fixed connection, but it’s also being used by other household members. Whenever they start downloading something, the quality and stability of my connection drops. Also the other way around, whenever I use streaming services that are extremely heavy on the bandwidth, they start experiencing issues as well.

The best solution here would be to split the total bandwidth in between all users equally, but I do not have access to the router configuration, and it doesn’t belong to me so I shouldn’t modify any settings in the first place.

This is why I decided to use my mobile phone for playing games via streaming services, to separate my network load from the rest of the house.