I recently had a similar problem while setting up Wi-Fi in a fairly large apartment. The connection worked fine near the router, but in other rooms I kept running into dead spots and unstable speeds, especially on the 5GHz band. I also wanted a simple way to create a separate guest network, because I didn’t really want visitors connecting to my main Wi-Fi. While comparing different models, I started looking into routers that could also work well as an access point, and the TP-Link Archer C7 came up a few times. I found this page useful: https://en.manual.ly/tp-link/tp-link-archer-c7-various-revisions/manual because it gave me a clearer idea of the setup options and features. From my experience, the most important things were stable 2.4GHz and 5GHz performance, guest WLAN support, easy configuration, and flexible placement. One thing I learned quickly is that 5GHz can drop off quite a bit through walls, so putting the router in a central spot and adjusting the antennas made a noticeable difference.