My apartment is also about 30m² so a single router is more than enough, but this is at my parent's in the countryside. The house is about 250m² on two levels. There is another much smaller building (around 42m²) about 50m away, and I have a cabin about 400m farther. I got Wi-Fi there using a set of GL.iNet GL-AR300M and a few antennas, but I'd like to have everything on the same mesh, and improve coverage in the house at the same time. Covering the barn another 30m away would also be a bonus.
Because of the size to cover, I like having the option to detach the antennas on some devices, so that I can position them better. My mother also don't want to see an "ugly" device with multiplie antennas poking out, sitting somewhere.
So far I like the Omada suggestions, and I'm leaning towards this solution.