Understood - possible solutions: Building a ramp, dividing the flat into different areas, removing the threshold, demolishing the house and building a new one but without thresholds.

https://www.helpyourrobot.de/produkt... this is probably the most elegant solution for it

Practical solution: simply stick a wooden board about 1 cm high to the floor. This way, the vacuum cleaner manages the step.

For obstacles that should not be driven over (e.g. chair legs): Stick bumpers on the legs and raise the obstacle. For door thresholds (necessary from about 2.5 cm) there are e.g. rubber mats/rubber ramps for cars or wheelchair users. Or noble: handmade ramps made of wood....