IMHO.If you can use Ethernet Backhaul, just use a cheap one to serve the room, for example RT-BE58U, below S$100 (or even below S$80) BNIB in Carousell.
If you need to use wireless backhaul, then that is another story, you have to post the floor plan with the details like the planned placement location of the main router and mesh node.
I plan for ethernet backhaul but i want to test wireless backhaul. I intend to lay one more cat6a so that my router and satellite node can see each other. I hope a door don't impact the wireless signal too much.