Below in this guide is shown examples of "Router mode" and "Access point mode":

https://www.tp-link.com/en/support/faq/3484/

It doesn't show the setup I intented so before I start wiring I'd like to be sure. 

Below is my idea: 

Inside:

INTERNET --- MAIN MODEM ROUTER --- Main Deco X50

Attic/Outdoor:

PoE-SWITCH in attic powering several X50-Outdoor (depending on coverage it will be 2-3 in attic and 1-2 outside). The X50-Outdoors would therefore not have any internet connection through the switch but only wireless/mesh to the Main Deco X50. 

Would it work or will the PoE switch in attic somehow react havoc to the wireless/mesh connection between Main X50 and the X50-Outdoors?

Why I want it like this?;

It would be easier to power the X50-Outdoor in the attic/outside via PoE from the PoE-Switch than setting up numerous new 230V outside outlets. I only have to setup one single 230V outside outlet for the Poe-Switch (outlet and PoE-switch will be in a sealed cabinet in attic).

Right now I have Deco M9 which works fine but I no longer want to look at the Deco power adapters and cables + I want better coverage outside.

The room where internet runs into the house was totally renovated 2 years ago so I would prefer not to install a new cable between Main Deco X50 and PoE switch. I no longer want to look at wires running outside wall from floor to ceiling + wife would consider killing me if I start grinding the walls of renovated rooms :)