Vampire taps are right out, but this is easier than you're making it.
If you are able to fish, you simply replace a bit of cable with more cable. E.G for A-X-B, you reroute the "B" end of the A-B cable to X, and add a X-B cable. When pulling the "B" end out, you can often use that to pull the new X-B cable in.
If you are not able to fish, then you come off the existing outlet with surface conduit.
However, maybe you should borrow a page from NEC. Because appliance cords are 1.8m, it requires sockets within 1.8m of any point on the wall (e.g. every 3.6m in a straightaway). That means you can put an appliance anywhere along a wall without using an extension cord. So just reach behind the furniture once to plug in and you're done.
Now, I gather this is for cell phone chargers and other things you aim to plug in frequently. In that case use the surface conduit to also come up to a useful height. The future homeowner can remove the surface conduit easily enough if they do not like it.
Lastly, at the time you are wiring the home, you are welcome to install as many sockets as you please, to greatly increase your chance of sockets not being buried behind furniture. For instance US NEC doesn't require 3.6m spacing, you can have 1.0m spacing if that floats your boat. Your local authority may have a restriction on the total number of outlets per circuit, however given this is ordinary living space and you have a reasonable reason, they may make an exception.
In the future when building or renovating, try specifying more than the legally minimum number of receptacles. Contractors often do you bare minimums in order to make their bid more competitive. But the incremental cost of adding 1 more outlet is very low at build time. The material cost in the US is maybe $2.50 (€2). If one hit a receptacle limit that called for another circuit, that is perhaps $25. So build/remodel time is the time to spec this!
By the way, vampire taps are right out because all splices have to be inside a junction box. Nobody makes junction boxes that wrap around in-place cable. Also remember you will need to go through permitting and inspection, especially in a multi-unit building.