Improve burglary protection at doors?

At this size, no. Burglars with trained monkeys or dwarfish accomplices are, in my opinion, not the norm in reality ;-)

At my parents' place, they entered through an approximately 60x40 window in the attic dormer (above the beach chair --> patio roof). Presumably young girls.

At this size, no. Burglars with trained little monkeys or diminutive accomplices are, in my opinion, not the norm in reality ;-)

There are said to be gangs of thieves who train their children ;)
That may not be comprehensible to you now, but it is so. The attentive reader knows that I work in an industry that has to deal with these phenomena. Therefore I can say: if someone wants to get in, they will do so. Less often through the front door, but rather through an inconspicuous window in a location that is not visible.

The attentive reader knows that I work in an industry that has to deal with these phenomena.

In the industry you mean, it is also known that although every perpetrator group has its "preferences," economic principles are still considered: low hanging fruits first; path of least resistance / least noise; spend little time on the break-in phase; and depending on the intelligence of the perpetrators, also a "reasonable ratio" between loot and penalty. The attentive reader also knows that I used to work in another industry dealing with this phenomenon (window manufacturing). Out of conviction, I also treat side doors and side windows with no less attention there. "At this size no" specifically refers to the dimension 40x40, where my fears would be limited to a gang of rubber people: no burglar likes to end up in the newspaper for being cut out by the fire department ;-)

I can recommend the Caucasian Ovcharka and a Doberman. Why two?

The Caucasian stays outside in winter (stall) and the Doberman sleeps in the house.

However, I only have problems when packages arrive, they are no longer delivered. But I can live with that.

Dog(s) should come, but only once there is a fence around the property :) Until then, all "entrances" have to be secured. Especially the windows that face the back, because there is only the garden there and a tall wooden fence towards the neighbor. And since we live only 1km from the A6 on-ramp towards the Czech Republic....

Fear Eats the Soul, Fassbinder, 1974, German feature film, Karsten