Network socket installation

Grooving is really a filthy job, but plastering so that you can no longer see it is not difficult. But since it's a used property: pay attention to boxed-in areas/coverings (like projections, often in corners), maybe there are pipe/other conduit shafts that can be used to get the cables up.

Ok, I will definitely do that. Thanks already for your feedback. Has anyone done it via [Kabelkanal]?

Underfloor heating?

For our first T-DSL connection (768kbit YEAH!!) I built a mini-network in a terraced house with cable ducts. Main riser with round pipe in the stairwell, then continuing in the ceiling corner, drilled through the wall, etc.. It works. If you have no demands.

No underfloor heating. Do you maybe have pictures? Unfortunately, I can't find anything online. I don't have high demands. I just don't want it to be extremely visible.

No sorry, that was over 15 years ago - there were no digital cameras back then..

If there is no underfloor heating, you might be able to drill through the ceiling, then you only have a short vertical slot up to the box.