Home security, how to implement it best?

That's exactly what I was getting at. I once attended a training on burglary prevention conducted by the police. The main message was very clear: the only thing that really helps is to create as much effort as possible.

Ok thanks, and how do you achieve that? So then RC3 is the only option left?

Ok thanks, and how do you achieve that? So then only RC3 remains?

In this case, yes. We weighed it up. The additional cost for the windows would have been exorbitant. We wanted KNX from the start. So exterior lighting on motion was easily implemented. Cameras around the house were also not "that" expensive. We excluded an alarm system from the beginning. By the time the cops arrive, the house has already been emptied anyway. And if not, the damage is done and the feeling that strangers have rummaged through your things is probably the worst anyway.
So we have RC2N, plus lighting plus cameras.
We asked around. There were frequent break-ins in the area. But no windows were ever smashed. There are many old buildings where windows were pried open. That doesn’t work quickly with RC2N either.

A sense of security is always subjective.

And the sense of security does not necessarily improve with the measures.
My advice:
Make it loud and uncomfortable for burglars, behave prudently, maintain a good neighborhood, forget the worries and live. You cannot live more safely than in Central Europe.
Anyone who breaks in here will find nothing of value because it simply is not there. Cash only in the form of stored coins, no valuable jewelry, no art that would be of interest to collectors, no valuable electronics, and due to the many windows, you can even see that.

Many correct points have already been made (Licht, Nachbarn, Warnschilder/Hund, keine Wertsachen). If video is desired after all, in my opinion the Blink camera series, for example, is sufficient and inexpensive.

Video per se does not bring anything in terms of deterrence or burglary prevention. With the usual commercially available cameras, especially at night, you can only repeatedly watch that someone was there. Recognizing usable details requires a different caliber. I am also into it, but it hardly has any practical benefit, except that you can possibly provide the police with usable material for their investigation.

As others have already written: maximize the effort for the visitors, no dark corners with entry opportunities, illuminate everything as brightly as possible, and possibly make noise. A colleague from prevention once told me that the "N" in RC2N stands for "Nonsense". Just saying :)

A colleague from prevention once told me that the "N" in RC2N stands for "Nonsense".

In fact, a normal pane (with RC2N) already makes quite a lot of noise when it is broken, so I gladly believe it when I am told that in nine out of ten cases the glass remains intact, and since that is then the only significant reinforcement of the higher classes, one can really consider how sensible that is for an average private house.