Home Networking

Hi all! I have the following problem: I have a 4G router which has to be positioned near the window otherwise connection is very slow, on the other side of the first floor of my house there is an ethernet cable that goes to the ground floor. I would like that from the end of the ethernet cable of the first floor the wifi connection became ethernet but without extending the wireless network itself, because I don't need it and in that case my devices connect to the extended network which is slower.

I tried with a range extender and an old router which supports WDS but both extend the wifi signal in addition to sending data to ehternet ports, that's exactly what I would like to avoid. I tried set WDS and then deactivate wireless radio on the old router but in that case it cannot connect to the main router wifi anymore. The ideal case would be a WDS setting that only receive wifi and sends to ethernet ports without resending it.

Do you think it is feasible? Otherwise I was thinking of changing SSID to the extender or to the old WDS router and hide it, in that way my devices would not connect to it, but it is annoying to have a wifi network which I don't use.

Here the scheme of the configuration.

https://preview.redd.it/5r4x9dfla31c1.png?width=1417&format=png&auto=webp&s=9b942e5ee42b6bc76ffe814a43f14ca0c68b9be3