How to change the floor plan?

It is "only" 300 sqm of floor space. I need at least 5m*6m of floor space for my billiard room. That would be feasible nowhere except the basement or the 3rd floor.

At most, some kind of extension/nesting at the front of the house would still be conceivable. But whether that comes close to a basement in terms of cost/benefit ratio, I can hardly assess, but I rather think not. Especially since then the storage rooms would be missing.

On the ground floor, I would swap the kitchen and the study. On days like today, your terrace will be anything but quiet, and can you still work reasonably there?

In a few years, a few teenagers will be sitting outside your bedroom door at night, and you’ll want to sleep undisturbed.

purely visually, your house looks like an office building in an industrial area.

Oh, I hadn’t really noticed this a month ago: the wing with the bedroom suite, with its three identical windows evenly spaced on the same axis, resembles an office above a row of three wide single garages. By simply breaking this "machine-punched" rhythm of the windows, one could introduce a "vitality" without additional costs.

No one will be working there anyway. Unfortunately, I don't have a home office. As of today, it will only be used as a guest room. Sure, my desk will go in there, but that will be leisure time. How else should one solve this, except by swapping the bedroom for the guest room? If everything is on one level, it can't be done any other way. Maybe one could think about it when the time comes.

I wouldn't like to swap the kitchen, because otherwise the guest would have to walk all the way through the hallway if they want to shower... As it is now, the guest basically has an almost separate area. You would just have to move the door to the north, then it would be perfect.