@YzPlayr 

Your are correct the real world use for Powerline is really all over the place.  There are many reasons for this. First understand the rating. For instance AV600 means that data transmits up to 600 Mbps between the adapter or in the Deco P7's case the Deco Nodes.  It is also the maximum speed in an ideal enviroment and not a guarantee. This is not a indicator of network speed you as a user will see.  That speed is dependent on your ISP package.  The second thing to understand is Powerline Adpaters can only work on the same panel.  If a sub panel is involved PLC adapters will not work. Third thing to understand is that each hop between circuits can slow your transmit speeds.  We have a thread that talks about this here: https://community.tp-link.com/us/home/forum/topic/150615?page=1.  Lastly load and interference.  Every thing that is connected to the power adds "noise" or interference.  Think of it like mud on a road. The more there is the slower you go.  You can reduce this by connecting items to a Surge Protector, which not only protects those devices from electical surges but also acts as a filter for the noise they add.  

The Deco P7 is one of our newest Mesh systems and is the first in the US to feature PLC backhaul.  You will still have the wireless backhaul and ethernet.  Even though Ethernet does not seem to be a viable option for you.  As long as you take measures above to limit the powerline noise you should have a good experiance with the Deco P7

Best Regards