Seeking feedback on Mesh network design

"I like the idea of running tests first. I would use an inexpensive WiFi router, like a TP-Link A7 and move a camera around to see what distances "work".

I did a few basic speedtests as a proxy for moving around the camera (due to the convenience of moving the phone around). Note that my ISP advertises a Downloads speed upto 100 Mbps, which I can indeed get when I run a speedtest using a Macbook Pro about 10-12 feet straightline distance from the router However for thr purposes of the test, I just used the phone for convenience.

• I measured the speed at the camera as a baseline: Download/Upload: ~16 / ~5 Mbps. This is approximately ~10-12 ft from the TP-Link router with a glass door in between.
• Stepping away another 10 feet away past the concrete compound reduces the speed to <1Mbps both download & Upload.

I went further away too, and speeds were lower or in some cases the speedtest (by Ookla app) would just fail.

At this point I do think trying out the Wireless signal strength with a Orbi router & extender together will likely give the best real-world data of what speeds are available when the extender is placed ~30 meters away from the router. I feel that will give a realistic sense of whether the bandwidth is indeed sufficient or not to support the cameras.

Thanks,
Sharath