The wireless router in the other room, which vendor is it? While WiFi standard doesn't support transparent bridges between two wired islands, different vendors came up with their own standard extensions. Unfortunately they are not compatible, but if both wireless devices are by same vendor, then it would most probably be possible to create such a bridge. In that case both wired parts of your LAN would act as if they were connected by wire.
The router is some Sagecom device with custom firmware for my ISP.
Have you thought of perhaps using MOCA adapters or Powerline adapters to get the signal to where you want it to go?
Another option, which may be a bit pricier is do a window to window transfer through wifi where line of sight LOS can be employed.
I will consider this.
I can basically do what I want currently with a TP-Link TL-MR3020 if I put it in AP mode and select repeater/bridge and just disable the WiFi AP, the main downside for me here is that I need a separate switch as I want more than one device on it.
I will maybe try setup things without Quickset and see what happens. All I want is basically to have a switch which is connected to my ISP WiFi router in the other room like there was a normal cable running to it.