EA7 wrote
For that reason i can connect 2nd floor decos to ethernet cable directly from wall ethernet socket
@EA7

If you have network layout this way, and switch is compatible with Deco, your Satellite Deco should use Ethernet. Satelite Deco will be among "Wired Devices on Home Network." It is also assumed from this diagram that other side of Ethernet cable from wall Ethernet socket on 2nd floor is connected to switch.
If your home network layout is different, you'll need to check document I gave you and/or draw diagram and share it, for others to review.
If network layout does not allow Satellite Deco to use Ethernet, Deco will keep using WiFi even if you connect it to network via Ethernet cable.
Also, that document I mentioned discusses in Q&A section what other reasons could be for Satellite Deco to not use network connection.