The difference in the amount of antennas in the Wi-Fi router
Answer:
I will not explain to you what is better and what is worse from a technical point of view, but if you consider TP-Link TL-WR941ND, and TP-Link TL-WR841ND, you will hardly notice any difference in Wi-Fi network coverage. As far as I know, the third Wi-Fi antenna on the TL-WR941ND is used for higher speeds. I would go with the older model, the TL-WR941ND it is a little more expensive, but it will be better. In terms of power, and probably the same wireless signal strength.
I had a TL-WR841ND. It was at the entrance to my apartment. So, in a large three-room apartment, there were places where the Wi-Fi signal was very poor. But it did. But everyone has different conditions (walls, interference, etc.). If there are problems with coverage, you can install a repeater.
If anything, read the article on choosing a Wi-Fi router for your home.