My house is 40 years old and was built on solid concrete at the time. 2 floors are covered (20x10m each). Currently Devolo Magic (Mesh Network) are connected with 2 adapters. In addition, there is also a Netgear R6300 WLAN router with dual band. On the WLAN router within 10m I achieve the full performance of 500 Mbps. The 1st Devolo on the 1st floor reaches 60 Mbit/s within 5m of the adapter. The other two (up to 20m from the base) also achieve 40-60Mbit/s. This is a considerable reduction in performance, but it is always enough to operate 2 x 4K TV and APPLE TV 4K.

Previously I had 1 Devolo 1200+ with 2 adapters available for the same residential volume. The performance was also 60 Mbit/s with each of these. The disadvantage was that if you moved within 200 square metres (per floor) you had to adjust the WLAN setting. This no longer happens with a mesh network.

Now I have 3 Devolo 1200+ devices lying around on the shelf (approx. 2 years old and as good as new) and they will hardly ever be used again. Interested in them? 50 Sfr incl. shipping, so almost free....

I was not at all satisfied with the performance. Depending on where the feed-in and the consumer were located, sometimes only about 5% of the download speed was available. Our flat is a good 10 years old. Power lines over fuse boxes reduce the speed dramatically.
I replaced the Devolo parts with two Asus parts. They are amazing. If you are not a radiation opponent, I can recommend them without hesitation.
ASUS ZenWiFi XT8 WiFi 6 AX6600 (2 Pack)
Read the reviews there. Personally, I would never go back to Devolo.
I hope my feedback helps you.