1Gigabit line but hardly anything arrives?

And I have the following problem: I have a gigabit line but only a fraction of it arrives. I'm a customer of Vodafone and have been very satisfied so far. I upgraded from then 400k to a 1Gigabit line and I was happy, but my joy has been very limited so far, but why did I already mention. I use the Powerline from Devolo because my router is too far away and I can't lay a 20m cable and so far I haven't had any problems with the Powerline (with the 400k line I had about 35-40Mb / s on Steam). When I ordered this gigabit line, I was still living in my old apartment and thought maybe there was a problem but the same problem now accompanies me here, too, I'll list everything below and attach a few pictures. Hopefully someone can help me.

Powerline: Devolo dLAN 1200+

Router: FRITZ! Box 6591 Cable

Provider: Vodafone

The router has no power saving mode and other modes can't be set either.

I deactivated the power saving mode for the Powerlines from Devolo.

Do a speed test directly on the router if you really want to know your internet speed.

Otherwise, your powerline is very likely the bottleneck. It is not unusual that the essentials deliver less than what it says on it because the power lines are very prone to failure and the stuff can even be influenced by devices that are plugged into the power supply.

Now a test with a cable on the router, then you can be sure that it is due to the powerline… Put both of them back and set them up again…

A simple mobile phone charger or similar power supply units in the line can lead to such losses…

And you won't be able to manage more than about 40mb before using powerline…

Unfortunately I don't have such a long cable at hand at the moment, but I will try it out and have actually only had good experiences with dLAN, well then you at least got to know the negative sides anyway, thanks for the answer.

I will do the days, unfortunately, I don't have such a long cable right now, but it's a shame I had only good experiences with the Powerline anyway, thanks for the answer.